Yitzhak Shamir, who emerged from the militant wing of a Jewish militia and served as Israel’s prime minister longer than anyone but David Ben-Gurion, promoting a muscular Zionism and expansive settlement in the occupied West Bank and Gaza Strip, died Saturday at a nursing home in Tel Aviv. He was 96.

Mr. Shamir had Alzheimer’s disease for at least the last six years, an associate said. His death was announced by the prime minister’s office.

A native of Poland whose family was wiped out in the Holocaust, Mr. Shamir was part of a group of right-wing Israeli politicians led by Menachem Begin who rose to power in the 1970s as the more left-wing Labor Party declined, viewed as corrupt and disdainful of the public.

Stubborn and laconic, Mr. Shamir was by his own assessment a most unlikely political leader whose very personality seemed the perfect representation of his government’s policy of patient, determined, unyielding opposition to territorial concessions.

Many of his friends and colleagues ascribed his character to his years in the underground in the 1940s, when he sent Jewish fighters out to kill British officers whom he saw as occupiers. He was a wanted man then; to the British rulers of the Palestine mandate he was a terrorist, an assassin. He appeared in public only at night, disguised as a Hasidic rabbi. But Mr. Shamir said he considered those “the best years of my life.”

His wife, Shulamit, once said that in the underground she and her husband had learned not to talk about their work for fear of being overheard. It was a habit he apparently never lost.

Mr. Shamir was not blessed with a sharp wit, a soothing public manner or an engaging oratorical style. Most often he answered questions with a shrug and an air of weary wisdom, as if to say: “This is so clear. Why do you even ask?”

In 1988, at a meeting of the political party Herut, he sat slumped on a sofa, gazing at the floor as party stalwarts heaped praises on him. Shortly thereafter, he said: “I like all those people, they’re nice people. But this is not my style, not my language. This kind of meeting is the modern picture, but I don’t belong to it.”

Rather than bend to them, Mr. Shamir often simply outlasted his political opponents, who were usually much more willing to say what was on their minds, and sometimes to get in trouble for it. To Mr. Shamir, victory came not from compromise, but from strength, patience and cunning.

“If he wants something, it may take a long time, but he’ll never let go,” Avi Pazner, his media adviser, once remarked.

In a statement on Saturday, Prime Minister Benjamin Netanyahu said that Mr. Shamir “belonged to the generation of giants who founded the State of Israel and fought for the freedom of the Jewish people.”

“As prime minister,” he added, “Yitzhak Shamir took action to fortify Israel’s security and ensure its future.”

Prime Minister Begin appointed Mr. Shamir as foreign minister in 1980. When Mr. Begin suddenly retired in 1983, Mr. Shamir became a compromise candidate to replace him, alternating in the post with Shimon Peres for one four-year term. Mr. Shamir won his own term in 1988. He entered the political opposition when Yitzhak Rabin of the Labor Party was elected prime minister in 1992. Mr. Shamir retired from politics a few years later, at 81.

A Hard-Line Approach

As prime minister, Mr. Shamir promoted continued Jewish settlement in the West Bank and the Gaza Strip, which Israel conquered in 1967; the Jewish population in the occupied territories increased by nearly 30 percent while he was in office. He also encouraged the immigration of tens of thousands of Soviet Jews to Israel, an influx that changed the country’s demographic character.

One of the most notable events during his tenure was the Palestinian uprising against Israeli control that began in December 1987, the so- called intifada. He and his defense minister, Mr. Rabin, deployed thousands of Israeli troops throughout the occupied territories to quash the rebellion. They failed; the years of violence and death on both sides brought criticism and condemnation from around the world.

The fighting also deepened divisions between Israel’s two political camps: leftists who believed in making concessions to bring peace, and members of the right who believed, as Mr. Shamir once put it, that “Israel’s days without Jerusalem, Judea and Samaria and the Gaza Strip are gone and will not return.”

The intifada dragged on year after year as the death toll climbed from dozens to hundreds. Israel’s isolation increased, until finally the rebellion was overshadowed in 1991 by the first Persian Gulf war.

During that war, at the request of the United States, Prime Minister Shamir held Israel back from attacking Iraq, even as Iraqi Scud missiles fell on Tel Aviv. For that he won new favor in Washington and promises of financial aid from the United States to help with the settlement of new Israeli citizens from the Soviet Union.

Then in the fall of 1991, under pressure from the first President George Bush and Secretary of State James A. Baker III, Mr. Shamir agreed to represent Israel at the Middle East peace conference in Madrid, Israel’s first summit meeting with the Arab states. There, he was as unyielding as ever, denouncing Syria at one point as having “the dubious honor of being one of the most oppressive, tyrannical regimes in the world.”

Yitzhak Shamir was born on Oct. 22, 1915, in a Polish town under Russian control to Shlomo and Perla Penina Yezernitzky. He immigrated to the Palestine mandate when he was 20 and selected Shamir as his Hebrew surname. The word means thorn or sharp point.

Members of his family who remained in Poland died in the Holocaust; his father was killed by Poles whom the family had regarded as friends. Memories of the Holocaust colored his opinions for the rest of his life.

In the British-ruled Palestine mandate, Mr. Shamir first worked as a bookkeeper and a construction worker. But after Arabs attacked Jewish settlers and the British in 1936, he joined the Irgun Zvai Leumi, the underground Jewish defense league. In 1940, the Irgun’s most militant members formed the Lehi, or Stern Gang, named for its first leader, Abraham Stern.

After the British police killed Mr. Stern in 1942, Mr. Shamir became one of the group’s top commanders. Under his leadership it began a campaign of what it called personal terror, assassinating top British military and government officers, often gunning them down in the street.

To the Jewish public, and even to the other Jewish underground groups, Mr. Shamir’s gang was “lacking even a spark of humanity and Jewish conscience,” Israel Rokach, the mayor of Tel Aviv, said in 1944 after Stern Gang gunmen shot three British police officers on the streets of his city.

Years later, however, Mr. Shamir contended that it had been more humane to assassinate specific military or political figures than to attack military installations and possibly kill innocent people, as the other underground groups did. Besides, he once said, “a man who goes forth to take the life of another whom he does not know must believe only one thing: that by his act he will change the course of history.”

Several histories of the period have asserted that he masterminded a failed attempt to kill the British high commissioner, Sir Harold MacMichael, and the killing in Cairo of Britain’s minister of state for the Middle East, Lord Moyne. When Mr. Shamir was asked about these episodes in later years, his denials held a certain evasive tone.

It was during his time in the underground that Mr. Shamir met Shulamit Levy, who was his courier and confidante, he wrote in his autobiography, “Summing Up.” The couple married in 1944, meeting at a location in Jerusalem and gathering people off the street as witnesses, said their daughter, Gilada Diamant. After a hasty ceremony in deep cover, each departed immediately for a separate city.

In addition to his daughter, Mr. Shamir is survived by a son, Yair, five grandchildren and seven great-grandchildren. His wife died last year.

For a brief period after World War II, the three major Jewish underground groups cooperated — until the bombing of the King David Hotel in Jerusalem on July 22, 1946. Scores of people were killed, and Mr. Shamir was among those arrested and exiled to an internment camp in Eritrea. But he escaped a few months later and took refuge in France. He arrived in the newly independent Israel in May 1948.

Entry Into Politics

Mr. Shamir was a pariah of sorts to the new Labor government of Israel, which regarded him as a terrorist. Rebuffed in his efforts to work in the government, he drifted from one small job to another until 1955, when he finally found a government agency that appreciated his past: the Mossad, Israel’s intelligence service. He served in several posts, including that of top agent in France, but returned to Israel and spent several years in business.

He joined Mr. Begin’s Herut Party in 1970 and was elected to Parliament in December 1973. When the Likud, or unity, bloc, which absorbed Herut, won power in 1977, Mr. Shamir was elected speaker. And when President Anwar el-Sadat of Egypt visited Jerusalem in November 1977, Mr. Shamir and Israel’s president, Ephraim Katzir, escorted him to the speaker’s rostrum for his speech. But the next year, when the Parliament voted on the Camp David accords, which set out the terms for peace with Egypt, Mr. Shamir abstained.

In 1979, when Moshe Dayan resigned as foreign minister, Mr. Begin proposed appointing Mr. Shamir to replace him. Yechiel Kadishai, chief of the prime minister’s office under Mr. Begin, recalled that Mr. Shamir was chosen because the prime minister did not want or need a powerful figure high in his cabinet.

“Begin had already established himself,” Mr. Kadishai said. “But by 1980, he wanted no competitors for power and selected Shamir because he was not so known in political circles.”

The liberal members of Mr. Begin’s coalition objected, so Mr. Begin named himself foreign minister until 1980, when Mr. Shamir finally took the post. The Labor Party saw his appointment as an mistake, since it considered him an extremist.

Mr. Shamir’s political opponents said that his laconic nature played into his handling of the massacres at the Sabra and Shatila refugee camps in West Beirut in September 1982, during Israel’s war in Lebanon.

On the evening of Sept. 16, Phalangists — Lebanese Christian militiamen — entered the camps and began killing hundreds of Palestinian men, women and children while the Israeli Army, largely unaware of the killings, stood guard at the gates.

The next morning in Tel Aviv, Ze’ev Schiff, a prominent Israeli journalist, received a call from a military official who told him about the slaughter. He rushed to the office of his friend Mordechai Zipori, the minister of communications, and told him what he had heard. Mr. Zipori then called the foreign minister, Mr. Shamir.

Mr. Shamir was scheduled to meet with military and intelligence officials shortly, so with some urgency Mr. Zipori told him to ask about the report he had received that the Phalangists “are carrying out a slaughter.”

Mr. Zipori remembered that Mr. Shamir promised to look into the report. But according to the official findings of an Israeli government commission of inquiry, Mr. Shamir merely asked Foreign Ministry officers to see “whether any new reports had arrived from Beirut.” When the meeting ended, Mr. Shamir “left for his home and took no additional action,” the report said.

Years later, Mr. Shamir said: “You know, in those times of the Lebanese war, every day something happened. And from the first glance of it, it seemed like just another detail of what was going on every day. But after 24 hours, it became clear it was not a normal event.”

Mr. Shamir was certainly not the only Israeli official who failed to act, but the commission found it “difficult to find a justification” for his decision not to make “any attempt to check whether there was anything in what he heard.”

When Mr. Begin retired in 1983, Mr. Shamir was designated his successor largely because of his position in the Foreign Ministry.

Even many in his own party thought Mr. Shamir would lose the election. And even after he took office, many saw this low-key, colorless man as a caretaker. In some ways he was. Asked once what he intended to do in his second full term in office, he said he had no plans except to “keep things as they are.”

“With our long, bitter experience,” he added, “we have to think twice before we do something.” Ethan Bronner and Jodi Rudoren contributed reporting. (Copyright 2012 The New York Times Company 07/01/12)