CAIRO, Feb. 1 -- Egyptian authorities have cracked down on opposition groups in recent days during a time of increasingly active efforts to stop President Hosni Mubarak from extending his 24-year rule in a referendum later this year.

On Saturday, police arrested Ayman Nour, leader of the opposition Tomorrow Party. Prosecutors charged him with falsifying petitions that resulted in the legalization of his party last October. On Monday morning, a court extended the initial four-day detention to 45 days, according to his wife, Gamila Ismail.

"It´s a message to him and every party that opposes the government," Ismail said. "Active parties that are serious about opening offices and genuinely recruiting followers will not be allowed."

Ismail said police raided Nour´s office and home. They confiscated computers from his house and rifled through medicine cabinets and Nour´s tobacco supply, Ismail said, adding, "It was certain they are looking for anything to frame him."

Last Friday, police arrested three activists at the Cairo book fair, an annual trade show, as they were handing out leaflets inviting the public to an anti-Mubarak rally scheduled for Friday.

The arrests followed several months of relative tolerance by the police. Opposition organizations have staged periodic demonstrations to oppose a fifth term in office for Mubarak as well as to voice suspicions that he plans to hand power to his son, Gamal.

"The arrests are an escalation," said Wael Khalil, a member of the Movement for Change, a coalition of anti-Mubarak groups. "There was interim improvement, but it looks like the old intimidation is back."

Police also confiscated books at the fair that demanded an end to Mubarak´s rule and arrested 10 students at Minufiya University northwest of Cairo on Sunday.

Government spokesman Ahmed Eissa declined to comment on the arrests. "Wait and see," he advised.

Mubarak´s opponents have organized numerous and sometimes quixotic efforts to head off another six-year term of office for the president. Three activists have announced they would run, though many observers say there is little chance that the government will institute multi-candidate elections.

Under current rules, parliament nominates a single candidate who is then ratified by referendum. Mubarak´s National Democratic Party controls more than 80 percent of the assembly seats. Change would require a constitutional amendment.

Muhammed Farid Hassanin, a former member of parliament and a declared candidate, campaigned last week at an athletic club near Cairo. He told 200 men in the audience that it was Egypt´s "shame" to have another pharaoh.

The speech set off earnest debate, with some audience members chanting in favor of Mubarak. In Hassanin´s view, it was a success nonetheless. "People say there is no alternative to Mubarak. For the first time, they have the chance to see one, even if it is just me," he said in an interview later. "Yes, it´s strange. A campaign without elections. But we must try everything."

His campaign and the campaigns of the two other challengers -- sociologist Saad Eddin Ibrahim and feminist writer Nawal Saadawi -- come in the context both of domestic ferment in Egypt and a perception that the U.S. government, long an ally of Mubarak, wants change.

Even though opposition leaders expect little from President Bush directly, they say his stand against "tyranny" at least provides a small opening for them. Hassanin conjectured that the presence of a foreign television crew at his sports club speech kept police from breaking up the rally. "At least they know outsiders are interested in Egypt," he said of the government.

Others point out that Bush could take small, symbolic steps. "No one expects Bush to turn off the money to Egypt or break relations," said Ibrahim, referring to the $2 billion in U.S. aid provided annually to Egypt. "But how about not inviting Mubarak to the White House? That would be a start."

Ibrahim was once jailed for 15 months on charges, later dropped, of sullying Egypt´s image and illegally receiving funds from the European Union to monitor 1995 elections. He acknowledges that his candidacy is effectively a publicity stunt. "I want to encourage others. We can have one, two, hundreds of candidates," he said.

Saadawi, the third candidate, has been traveling outside of Egypt and could not be reached for her views. She has issued statements arguing that it would be fit and proper for a woman to rule Egypt and has called for Egypt to fight "plunder and aggression by the U.S. and Israel."

While these symbolic candidacies are in full swing, Mubarak´s intentions have been difficult to pin down. In early January, Kamal Shazli, assistant secretary general of Mubarak´s National Democratic Party, announced that the party had already selected the president as its candidate. Gamal Mubarak quickly contradicted him and labeled the announcement "contemptuous of the people´s will."

During interviews with foreign and Egyptian reporters this month, President Mubarak danced around the issue. At one point, he said he had yet to decide. Then, to the satellite television channel al- Arabiya, he hinted he would run if the people wanted him to.

In mid-January, he called an Egyptian talk show and spoke wistfully of the difficulties of being president. "It is very tough to be in office. It is no luxury at all," he said. "Anyone who would be president of Egypt will have to work until he is drained of energy. It is a job that consumes one´s health, time and nerves.

"I cannot go visit anyone because I am afraid that security will be a bother," he said. "I cannot have a walk like anyone else. . . . I am stripped of my freedoms." With those caveats, he welcomed competition. "Let them all run," he said.

The invitation did not translate into support for constitutional change, however. According to the pro-government al-Ahram Weekly newspaper, Mubarak told a closed meeting of "intellectuals" on Jan. 16 that "foreign powers" were funding the demand for constitutional changes. The same day, his party´s secretary general, Safwat Sharif, repeated the accusation.

Last Saturday while traveling to an African summit, Mubarak told reporters that the current system of having parliament choose the president has kept Egypt stable and that demands for constitutional change were pointless.

In any case, some opposition leaders think Mubarak is unstoppable for now. In an interview two days before his arrest, Ayman Nour said, "We expect him to run and to win, though that is not what we hope. The struggle is just beginning."

Nour´s party has come up with a program to introduce rule by parliament in Egypt, with a weak presidency. Another group, the Committee in Defense of Democracy, wants to make the president more answerable to parliament. (© 2005 The Washington Post Company 02/02/05)