The Syrian Red Crescent has said it delivered some food and medical aid to beseiged rebel-held areas of the central city of Homs today despite its vehicles being fired on.

One driver was wounded but the Red Crescent said on Twitter: "Although the team was shelled and fired upon we managed to deliver 250 food parcels, 190 hygiene kits and chronic diseases medicines."

In an earlier Tweet it said: "Shots fired targeting aid trucks and the team,"  without accusing anyone, government forces or rebels, of being responsible.

It also said a Red Crescent "aid truck driver (was) injured."

"Mortar shells falling in close proximity near the team and aid trucks that moved into Old City," another tweet had said.

State news agency SANA said four Red Crescent volunteers were wounded "by gunshots fired by armed terrorist groups," as an aid convoy was entering the Old City.

The regime calls rebels trying to topple the government "terrorists".

Homs governor Talal al-Barazi said "two vehicles carrying humanitarian assistance entered the Old City," but that "terrorist groups prevented the entrance of other vehicles by firing mortar rounds on the road."

The UN set out to deliver aid to civilians trapped in rebel-held areas of the Old City for more than 600 days of a choking army siege, a day after evacuating dozens from there.

Activists for their part accused the regime of launching mortar and tank fire against the convoy.

"The Red Crescent vehicles entered (the old City) with five UN cars and two trucks carrying humanitarian aid," said an activist in the besieged neighbourhoods who goes by the name Yazan.

"Just as they were entering, the area where they were and where civilians were gathered was bombed, wounding several people," he said.

Yazan added that the rounds were launched from two separate areas, one bordering the besieged neighbourhoods, the other some 200 metres (yards) away. Both areas are under regime control.

The UN and Red Crescent were scheduled to bring in humanitarian assistance for some 3,000 people trapped in Homs since June 2012, under a UN-supervised truce agreement between the regime and the rebels.

Under the agreement, 83 civilians were evacuated Friday.