At least four workers were said to have been injured by gunfire yesterday as they entered a rebel-held area of the city.
The Syrian Arab Red Crescent said on Twitter that an aid truck driver had been wounded after shots were fired at the convoy, and added that mortar shells also landed close by as the vehicles moved into the Old City. It also posted a picture which appeared to show a bullet hole in the back window of a Red Crescent car.
The United Nations is overseeing efforts to deliver food, water and medicine to about 3000 civilians in rebel-held areas.
The government and rebels accused each other of violating a ceasefire after mortar fire yesterday morning delayed an earlier attempt to bring in aid.