Renewed fighting hampered a U.N. relief effort in Syria's war-battered city of Homs on Saturday, breaking a three-day humanitarian pause agreed by both sides.
The Syrian Red Crescent says the driver of one its aid trucks was wounded when unidentified assailants fired at its vehicles.
The relief group also says mortar shells fell near the convoy. Shelling was reported elsewhere in Homs.
The Syrian government and the opposition blame each other for breaking the cease-fire, which was intended to let in aid and allow civilians to leave.
U.N. Emergency Relief Coordinator Valerie Amos says she is deeply disappointed the pause in fighting was broken and aid workers deliberately targeted. She called it a stark reminder of the dangers civilians and aid workers face every day in Syria.
The U.N. says it still plans to go ahead with its humanitarian mission in Homs to bring food, medicine, and other basic supplies to thousands of trapped civilians.
A year-long blockade of Homs by Syrian government forces has created severe food shortages.
Also Saturday, opposition activists said Syrian government forces renewed their assault on the northern city of Aleppo.
The Syrian Observatory for Human Rights says at least 15 people were killed when government forces dropped crude explosives called barrel bombs on the city.
The next round of peace talks between the Syrian government and opposition is due to open Monday.
The talks, organized by the United States and Russia, have made little progress so far in ending Syria's civil war. More than 130,000 people have been killed and 9 million forced from their homes since the conflict began in 2011.