Nearly a dozen civilians were evacuated from besieged parts of the Syrian city of Homs Wednesday before the operation was halted when shots were fired, the governor told AFP.
Elsewhere, the Syrian Observatory for Human Rights said at least 11 regime forces were killed when rebels detonated explosives under a building in the Old City of Aleppo.
"The operation allowed the evacuation of 11 civilians from Bustan al-Diwan and Al-Hamidiya," Governor Talal Barazi said, but it was halted because of "obstruction by armed men who opened fire at the crossing."
Barazi did not identify the gunmen, but "armed men" is a common regime term for rebels fighting to oust President Bashar al-Assad.
He added that the evacuation had not been coordinated with the United Nations but with "elders and clerics."
Barazi earlier told state TV that most of those evacuated were women, children and the elderly.
The United Nations and Syria's Red Crescent began operations to evacuate trapped civilians and deliver aid inside besieged parts of Homs on February 7.
The operation has allowed out some 1,400 of the estimated 3,000 people trapped in Homs for more than 18 months by a government siege that forced residents to survive on little more than olives and wild plants.
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The work was made possible by a ceasefire that was extended twice, but expired on Saturday night.
Barazi had said Sunday that "armed groups" prevented the operation from resuming. It was not possible to confirm the claim.
The chaotic UN and Red Crescent evacuation process saw aid convoys come under fire. Shelling killed more than a dozen people despite the nominal truce, with the warring sides trading blame for the violations.
Following their evacuation, around 400 men and boys aged 15-55 were detained by authorities for investigation, raising concern among UN and Red Cross officials.
Barazi said Saturday that 390 male evacuees had left Homs, with 211 released so far.
Last week the United Nations said 430 men and boys had been detained with just 181 released.
The Homs truce came about despite the failure of the latest round of Geneva peace talks aimed at ending the nearly three-year conflict, which has claimed an estimated 140,000 lives.
In the northern city of Aleppo, the Observatory said rebels had dug a tunnel leading to a building being used by regime forces in the Old City and detonated explosives in a massive blast that killed 11.
At least 14 were wounded, and several surrounding buildings were damaged, Observatory chief Rami Abdel Rahman told AFP.