Renewed fighting hampered a U.N. relief effort in Syria's war-battered enclave of Homs on Saturday, a day after a three-day humanitarian pause in violence took effect.
On Twitter, the Syrian Red Crescent said the driver of one its aid trucks was wounded after unidentified assailants fired shots at the vehicle.
Also, mortar fire rocked some regions of Homs on Saturday.
The Syrian government and the opposition have blamed each other for the unrest, a violation of the pause intended to allow the delivery of aid to rebel-held areas of the city and allow civilians to leave.
In another development Saturday, opposition activists said Syrian government forces had renewed their assault on the northern city of Aleppo.
The opposition Syrian Observatory for Human Rights says at least 15 people were killed after government forces dropped crude explosives called barrel bombs on the city.
The U.N. says it still plans to go ahead with its humanitarian mission in Homs.
U.N. officials say the aid includes food, medical and other basic supplies for thousands of people.
They say 83 civilians -- women, children and elderly people -- were evacuated from Homs on Friday.
Video uploaded to a social media site appears to show heavily damaged buildings and rubble in the background as relief workers escort civilians from Homs. An unidentified person says "The elderly people are leaving the besieged Homs. God bless you!"
A year-long blockade of Homs by Syrian government forces has created severe food shortages.
Russia said Mr. Assad's government made an agreement with the U.N. on Thursday for a three-day cease-fire to allow in aid.
Syrian Deputy Foreign Minister Faisal Makdad said Friday the government will take part in the next round of peace talks with the opposition. The new talks are set to open Monday.
The talks, organized by the United States and Russia, have so far made little progress 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.