A roadside bomb struck a Syrian military truck near Deraa, wounding six soldiers just seconds after a convoy carrying the head of the UN observer mission passed by.An Associated Press reporter who was travelling in the UN convoy said the explosion blew out the military truck’s windows and caused a plume of black smoke. Vehicles in the UN convoy were not hit."We were driving behind the UN convoy as protection when a roadside bomb exploded, wounding a first lieutenant and five troops,” a soldier who asked to be identified only by his first name, Yahya, told AP at the scene.At least three bloodied soldiers were rushed away.The blast went off after the head of the UN observer mission, Major General Robert Mood, headed into the southern Syrian city with a team of observers and a convoy of journalists.The explosion was more than 100 metres behind the convoy. It was not clear who was behind the blast.Renewed violence Meanwhile, troops pounded a rebel hideout near Damascus killing at least three people on Wednesday, among them two soldiers and one civilian, the UK-based Syrian Observatory for Human Rights said.Residents of Douma, about 13 kilometres from the capital, reported heavy shelling since dawn and bursts of gunfire in the town, the Observatory said.Rebels fighting to overthrow the government of President Bashar al-Assad have apparently sought refuge in Douma.In Damascus itself, clashes erupted briefly between a security patrol and rebels in the neighbourhood of Maisat, but there were no casualties, the Observatory said.