More than 600 civilians have been evacuated from the rebel-held Old Quarter of the central Syrian city of Homs, state media report.
This was despite mortar fire and shooting which activists say killed several people and wounded others.
UN and Syrian Red Crescent teams also managed to deliver relief supplies to the quarter, which has been besieged by government forces for more than a year.
On Saturday aid workers were trapped under fire there for several hours.
The BBC's Jim Muir says a convoy with relief supplies went into the Old Quarter on Sunday, and then vulnerable civilians were brought out - mainly women, children and the elderly.
He says they looked pale and stressed, after surviving for months in violent siege conditions with very little food or medical care.
The Wall Street Journal's Sam Dagher, in Homs, has tweeted that more than a dozen men who came out with the evacuees were detained by security forces and taken away to an unknown location.
Sunday is the final day of what was agreed as a three-day humanitarian truce.
The governor of Homs, Talal al-Barazi, has said the ceasefire may be extended by a further three days, to allow all those who might want to leave the chance to do so.
Elsewhere, opposition activists said at least 11 people were killed in the northern city of Aleppo when government helicopters dropped barrel bombs - crude weapons comprising cylinders packed with explosives and metal fragments - on rebel-held neighbourhoods.
The operation to help trapped civilians in Homs was the one concrete agreement reached at recent peace talks in Geneva, which are due to resume on Monday.
A UN/Red Crescent aid convoy came under attack from mortars and gunfire as it was leaving Homs on Saturday.
Syrian authorities have blamed the attack on rebels, but they in turn say that President Bashar al-Assad's forces were responsible for the incident.
UN humanitarian chief Valerie Amos has insisted that the UN and aid agencies will not be deterred by the weekend's violence.
She said the events were "a stark reminder of the dangers that civilians and aid workers face every day across Syria".
The Red Crescent, in a joint operation with the UN, is trying to deliver food, water and medicine by truck to some 3,000 civilians in rebel-held areas.
Homs has been a key battleground in the uprising against President Assad.
The army launched a series of major attacks to recapture rebel areas in the Old Quarter in the beginning of 2012, with almost daily bombardments.
Thousands have been killed, large areas have been reduced to rubble, and many neighbourhoods lie in ruins.