By Khaled Yacoub Oweis ,Reuters

AMMAN — Syrian rebels killed at least seven pro-government militiamen in a Damascus suburb on Wednesday, activists said, and an explosion wounded eight soldiers escorting U.N. ceasefire observers in the southern province of Deraa. 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 ceasefire 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 al-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 U.S. envoy to the United Nations declared on 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.” On Wednesday a bomb exploded in Deraa close to a convoy of U.N. monitors, led by Major-General Robert Mood, tasked with observing the implementation of Annan’s April 12 ceasefire 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 U.N. 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 afterwards.

Despite an initial lull in fighting, the agreed ceasefire has not taken hold. Nor has the carnage stopped, despite a parliamentary poll on 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 ceasefire 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.