"We entered with medical aid to Moadimayat al-Sham and we are distributing food aid in the buffer zone" between regime and rebel forces, Pawel Krzysiek, spokesman in Damascus of the International Committee of the Red Cross, told AFP.
He said the joint convoy of the ICRC and the Syrian Arab Red Crescent was made up of 10 trucks loaded with food supplies and two with medical equipment and medicine.
But the United Nations in January re-classified Moadamiyat al-Sham as a besieged town with scant food supplies after the regime tightened access.
The United Nations has been struggling to deliver aid to about 480,000 people in besieged areas.
The UN Security Council, for its part, has adopted resolutions demanding an end to sieges imposed by both rebel and government forces as a weapon of war, but these have been largely ignored.
After mounting international outrage over the starvation of civilians, aid has been delivered since the start of the year to Madaya, another town under a regime siege, as well to rebel-besieged Fuaa and Kafraya.