"No plan to withdraw the observers is on the agenda of the Arab ministerial committee meeting on Syria" in the Egyptian capital on Sunday, the pan-Arab body's deputy secretary general, Adnan Issa, said.

"We are not talking about a pull-out but reinforcing the mission," Issa added. He said there were now 153 observers in Syria with another 10 expected to arrive on Saturday from Jordan.

"The Arab states want the observers to continue their mission, and that it be reinforced," he said.

Activists have called for the League observer mission that has been in Syria since Dec. 26 to admit its failure to stem the bloodshed in the crackdown on dissent and hand the task over to the United Nations.

Sunday's meeting in Cairo, where the Arab League has its headquarters, is expected to be briefed by the head of the observer mission.

Meanwhile, crowds waving Syrian flags and pictures of President Bashar Assad gathered on Saturday to bury 26 people who the authorities said were killed by a suicide bomber at a busy Damascus crossroads.

The opposition Syrian National Council has accused the government of staging Friday's explosion to try to bolster its contention that it is fighting foreign-backed "terrorists," not a popular pro-democracy movement.

A cortege of ambulances, lights flashing, bore the flag-draped coffins of victims to a Damascus mosque after driving through streets lined with mourners, state television showed.

Qatari Prime Minister Sheikh Hamad bin Jassim Al-Thani, who heads the observer committee, told Al-Jazeera TV the monitors should not stay to "waste time" since Syria was not implementing the deal.

He said the Syrian Army had not left cities as required and the killing had not stopped since the observers began work on Dec. 26. "With great regret, the news is not good," he added. Security forces trying to crush anti-Bashar protests around Syria killed four civilians in Homs on Saturday, and three people died in Harasta from wounds inflicted on Friday, the opposition Syrian Observatory for Human Rights reported.

It also said security forces had killed 20 civilians and three army defectors on Friday.

Scores of people have been reported killed since the observers arrived, adding to a death toll that the United Nations says has already topped 5,000 since the uprising erupted in March, inspired by Arab revolts elsewhere. Qatar is proposing to invite UN technicians and human rights experts to help Arab monitors assess whether Syria is implementing the League's plan, sources at the Arab League said. A source said the ministers meeting on Sunday might request that U.N. staff helping the mission be Arabs.

League sources said the foreign ministers, who will consider an initial report by the monitors, would also discuss measures to allow the mission to operate more independently of the Syrian authorities.

Arab League chief Nabil Elaraby, in a statement posted online, condemned the "terrorist explosion" in Damascus and voiced "great concern at the escalation of violence in Syria."

Syrian Interior Minister Ibrahim Al-Shaar had promised earlier to hit back with an "iron fist" for the blast, which he said killed 26 people, including 15 who could not be identified.

Arab states are wary of instability in Syria, which the Arab League has suspended for failing to implement its peace plan earlier. Syria is a major power-broker in the region, allied with Iran and the Lebanese Hezbollah group.

Hezbollah blamed the blast on "evil American forces and those under its control in our region to punish Syria for its firm support of resistance forces against the Zionist enemy (Israel) and the West."

US State Department spokeswoman Victoria Nuland said that, as with previous attacks, Syria had blamed "just about everybody": The opposition, Al-Qaeda and the United States.

"At the present time we can't say one way or the other how this happened but what we can say is that, obviously, we condemn the attack," she said.