A truck carrying humanitarian aid makes its way to besieged civilians in old Homs city February 9, 2014, in this handout released by Syria's national news agency SANA. [Photo/Agencies]

BEIRUT  — Hundreds of civilians were evacuated Sunday from the besieged Syrian city of Homs, braving gunmen spraying bullets and lobbing mortar shells to flee as part of a rare three-day truce to relieve a choking blockade. Dozens were wounded as they fled.

The cease-fire came as Syrian officials arrived in Switzerland for a new round of talks with opposition activists-in-exile to try to negotiate an end to Syria's three-year conflict.

More than 600 people were evacuated from Homs on Sunday, said Governor Talal Barrazi. The operation was part of a U.N.-mediated truce that began Friday between the government of President Bashar Assad and armed rebels to allow thousands of women, children and elderly men to leave opposition-held parts of the city, and to permit the entry of food and supplies.

Forces loyal to Assad have blockaded rebel-held parts of Homs for over a year, causing widespread hunger and suffering.

Dozens of people were wounded when they came under fire as they waited at an agreed-upon evacuation point in the rebel-held neighborhood of al-Qarabis, according to three activists based in Homs, who spoke to The Associated Press by Skype.

Despite the gunfire and exploding mortar shells, hundreds of women, children and elderly men ran toward a group of Red Crescent workers waiting less than a mile (kilometer) away, said an activist who gave his name as Samer al-Homsy. The Syrian activists said the gunfire came from a government-held neighborhood.

The Syrian news agency SANA also reported that civilians came under fire, but blamed "terrorists," the government term for rebels.

At least four busloads of civilians were shipped out, according to footage broadcast on the Lebanese television station al-Mayadeen. Wide-eyed children, their prominent cheekbones suggestive of malnutrition, tumbled out of a bus, assisted by aid workers.

"Our life was a disaster, we had no food, no water," one distressed woman said.

There was nothing, my children are all sick. They were thirsty," she said, standing with a group of exhausted-looking children as khaki-clad Syrian soldiers, Red Crescent workers in red jump suits and U.N. workers in blue protective vests gathered around the buses.

Some evacuees were to be hosted in government-run shelters, others were going to join relatives in safer areas, while still others said they did not know where they were going.

Khaled Erksoussi of the Syrian Red Crescent, which is assisting the operation, told the AP that the agency hoped to evacuate as many civilians as possible before the truce expires Monday.