Syrian rebels killed at least seven pro-government militiamen in a Damascus suburb yesterday, activists said, and an explosion wounded eight soldiers escorting UN cease-fire observers in the southern province of Daraa.

The Damascus attack with rocket-propelled grenades on a bus carrying the fighters through the suburb of Irbin prompted the army to seal off the area and respond with shelling, activist Mohammad Saeed said.

Sustained violence in Syria, nearly four weeks after a cease-fire deal brokered by mediator Kofi Annan, has led to warnings this week from the Red Cross, Arab League and Annan himself that the country is slipping into civil war.

Annan’s truce was part of a wider plan aimed at ending 14 months of unrest, starting with peaceful but violently repressed demonstrations against President Bashar Assad and moving into an armed conflict that the International Committee of the Red Cross says now meets its definition of civil war in some areas.

Bloodshed in Syria has sharply divided world powers. The US envoy to the United Nations declared Tuesday that Assad’s government had not fully implemented any part of Annan’s plan, while Russia’s ambassador, who has been more supportive of Damascus, said “things are moving in a positive direction.”

Yesterday a bomb exploded in Daraa close to a convoy of UN monitors, led by Maj. Gen. Robert Mood, tasked with observing the implementation of Annan’s cease-fire deal. The pro-government Addounia television said eight members of the security forces accompanying the monitors were wounded in the blast, but none of the UN observers was hurt.

“The important thing is not speculating about who was the target, what was the target, but to make the point that this is what the Syrian people are seeing every day and it needs to stop,” Mood said afterward.

Despite an initial lull in fighting, the agreed cease-fire has not taken hold. Nor has the carnage stopped, despite a parliamentary poll Monday which the government promoted as a milestone on its path to reform, but which the opposition dismissed as a sham and boycotted. Beyond the cease-fire and monitoring mission, Annan’s plan also calls for free access for journalists, humanitarian aid access and political dialogue between the government and opposition. So far, 60 of some 300 monitors have arrived with the whole team expected to be assembled by the end of May.

Lebanese residents in the border town of Al-Qaa said Syrian troops fired across the border into Lebanon yesterday, killing a 75-year-old woman and wounding her daughter. In the northern province of Idlib, one man was killed and three others wounded during heavy clashes, the Syrian Observatory for Human Rights said. A Reuters journalist in Idlib city heard gunfire throughout the night.

Heavy clashes were also reported in Hama city and in Deir Al-Zor, where residents say government forces carried out raids and arrests. Two security members were killed and one man was killed by unknown gunmen, the British-based Observatory said.

Opposition sources in Rastan, about 30 km north of Homs city, said UN observers had been unable to visit the town due to a third day of bombardment and shooting there. Two people were killed and seven wounded on Wednesday.

The United Nations says Syrian forces have killed 9,000 people since the uprising erupted in March 2011. Syrian authorities blame the violence on foreign-backed militants who they say have killed 2,600 soldiers and police.

Because of the conflict one million Syrians now need humanitarian help, according to a UN mission which visited in March. The United Nations is preparing a major aid operation, backed by a $ 180 million appeal, but has yet to reach agreement with Damascus on how the assistance will be delivered.

Syrian envoy to Geneva Faysal Khabbaz Hamoui said talks were continuing but that his country’s needs were not huge. “Syria is not Somalia. Syria is not Haiti,” he said.

In New York, Syria’s UN envoy Bashar Ja’afari displayed a CD Tuesday containing what he said were confessions of 26 Arabs caught in Syria who had come from Libya, Tunisia and elsewhere via Turkey and Lebanon “to perpetrate terrorist acts.”