A staff worker for the Syrian Arab Red Crescent relief organisation was wounded in an attack on a humanitarian convoy near Damascus, the International Committee for the Red Cross (ICRC) said in a statement on Sunday.
Air strikes hit rebel-held districts east of Damascus on Thursday for the first time in weeks after shells landed in parts of the capital controlled by the Syrian government.
Fighting and bombardment around Damascus have eased significantly since Russia, Turkey and Iran agreed a deal for "de-escalation zones" around Syria in an April meeting in Astana, Kazakhstan. Talks between different Syrian and foreign factions are due to take place early next month.
"The 37-truck convoy from the ICRC, Syrian Arab Red Crescent and the United Nations was to deliver food, medicine and daily essentials to 11,000 people in the town of East Harasta," the ICRC said.
The aid worker was seriously wounded in a shooting that took place in on Saturday evening, it said.
"Residents in East Harasta have not received any humanitarian aid for nearly eight months. Renewed security guarantees are needed in order to proceed with this planned aid delivery."
After six years of war between President Bashar al-Assad and rebels seeking to oust him, hundreds of thousands of Syrians have been killed and more than half the country's pre-war population made homeless.