A suicide bomber attacked a group of Syrian security service members near a mosque in a Damascus suburb on Friday, killing at least nine people and wounding dozens of others, said the state news media, which also reported at least two other bombings around the capital in the most recent signs of the erosion of the United Nations-monitored cease-fire.

Activists and residents in the neighborhood of the mosque in the suburb of Midan, south of the capital, said that some civilians had been wounded in that blast and that security forces opened fire immediately afterward, scattering crowds of worshipers.

One person was killed and several were wounded in the two other blasts, according to the state news media.

The three bombings followed the reported killing of security service members in and around Damascus this week and were the latest in a series of attacks that the Syrian government has attributed to terrorists seeking to destabilize the government. Syrian state television said the bomber in Midan detonated his weapon after approaching a group of security service members assembled near the mosque to monitor possible protests after Friday Prayer.

Some civilians blamed the government. One resident said worshipers, who had been planning to join antigovernment protests, were targeted, while some opposition activists said the Syrian government had itself attacked security forces to make the uprising, which began as a broad- based protest movement, look as if it were devolving into violent extremism.

The United Nations secretary general, Ban Ki-moon, said he was “gravely alarmed” by the continued killing in Syria. “Shelling and explosions in residential areas go on,” he said in prepared remarks at a news conference in India. “U.N. military observers report of heavy weapons in population areas. This is in clear contravention to what the Syrian government has already agreed.”

Mr. Ban’s remarks underscored the international community’s inability to halt the violence despite sanctions, two separate observer missions and the declaration of a cease-fire more than two weeks ago. Also on Friday, Mr. Ban announced the appointment of Maj. Gen. Robert Mood of Norway to oversee the United Nations mission, which is expected to expand in the coming weeks to 300 military observers from the advance guard of 15 now in the country.

The mission has been roundly criticized by civilians who have gone so far as to parody the monitors as blind men, especially after the leader of the initial group of observers, Col. Ahmed Himmiche of Morocco, said last week that they would not head into the streets on Fridays, when big demonstrations often occur. A spokesman for the mission later said there was no blanket rule.

On Friday, a small contingent of inspectors arrived in Idlib, the restive northwestern province, and briefly toured a town, Maarat al- Noaman, according to an activist speaking by Skype. “A huge crowd received them,” said the activist, who spoke on the condition of anonymity. “Despite threats by the government forces, people joined today’s protests.” The monitors were expected to make a more complete tour on Saturday, the activist said.

The Local Coordination Committees, an activist group, put the death toll in protests around Syria at 18, including 5 in Homs, 3 in Idlib and 4 in Damascus and its suburbs. The Friday count was lower than in recent weeks, though it did not include the Midan suicide attack, which the group described as “the terrorist bombing that the regime fabricated.”

The Syrian government and opposition activists have each sought to win over public opinion, and in recent days, including Friday, the government has employed what has been a mainstay of the opposition: quickly trying to frame the debate over who is at fault. The state news agency published gory photographs of human remains on the English-language version of its Web site, echoing gruesome images regularly shared by activists on YouTube and attributed to Syrian government attacks.

Health Minister Wael Nader al-Halqi said on state television that seven of the dead were police officers, The Associated Press reported.

Reached by Skype, an activist in Midan said the blast there had occurred outside the Zein al-Abiddine mosque, where some of the largest Friday protests have occurred. “Worshipers were preparing to leave the mosque to demonstrate,” said the activist, speaking on the condition of anonymity. “While leaving, a huge sound was heard,” he said, adding that it was “obvious the blast targeted the worshipers.”

A resident who had been praying in the mosque said the blast had shaken its walls and windows. Emerging from the building, the resident, who gave his name only as Ma’amoun, described a chaotic scene, with security service members screaming and ambulances and cars rushing the wounded to a nearby hospital.

The second bombing occurred in Al Sinaa, a neighborhood of the capital near the state-owned Internal Transportation Company, which provides buses to security forces, according to a resident who identified himself only as Khalid. He said several people were taken to a hospital. The third blast went off near a highway overpass by a military museum. The state media said several people had been wounded, but a witness there said no one had been in the area at the time of the explosion.

J. David Goodman reported from New York, and Hwaida Saad from Beirut, Lebanon. An employee of The New York Times contributed reporting from Damascus, Syria. (Copyright 2012 The New York Times Company 04/28/12)