Syrian rebels, including jihadists linked to Al-Qaeda, have taken control of the historic Christian town of Maalula north of Damascus, a watchdog and residents said on Sunday.
The town, home to around 5,000 people, is strategically important for rebels, who are trying to tighten their grip around the capital and already have bases south and west of Damascus.
Maalula, around 55 kilometres (34 miles) from Damascus, could also be used as a launching point for attacks on the highway between the capital and Homs, a key regime supply route.
The battle for the town left at least 17 rebels dead and more than 100 wounded overnight, the Syrian Observatory for Human Rights said, adding that dozens of regime forces and pro-militia members were also killed or wounded.
"Overnight, Syrian regime troops moved into the village, but rebel forces sent reinforcements and were able to take control of the entire town," Observatory director Rami Abdel Rahman told AFP.
He said Al-Nusra Front, which has pledged allegiance to Al-Qaeda leader Ayman al-Zawahiri, was among the forces that had taken control of the town.
Battalions affiliated with the Western-backed Free Syrian Army had also entered Maalula, he said.
A resident, reached by phone, confirmed that regime forces had withdrawn and rebel forces were now in control.
"The rebels are inside Maalula, all of Maalula. The government troops have pulled out of Maalula," the resident said.
Abdel Rahman said "fierce fighting broke out between regime forces and rebel fighters overnight, and the soldiers withdrew to the outskirts of the town".
Troops were still stationed around the town, according to a rebel commander in the area, including at a checkpoint where fighting began on Wednesday after an Islamist rebel blew himself up in an attack.
He confirmed that there was little military activity on Sunday, and said civilians had begun fleeing the town on Wednesday.
The exodus has left Maalula virtually empty, residents say.
"There's no one left in Maalula, everyone has fled," 73-year-old George told AFP by phone from the town.
He said he had decided to stay behind with his brother, but his wife and their two daughters had left for Damascus on Friday.
"People are afraid, they are terrified," he said.
A nun at the Maalula's Greek Orthodox Mar Takla convent said its inhabitants were safe.
"The sisters and the orphan children are fine," she told AFP by phone.
"All the residents have left to Damascus. The houses are empty, it's a ghost town." Picturesque Maalula is nestled under a large cliff and is considered a symbol of the Christian presence in Syria.
Many of its inhabitants speak Aramaic, the language spoken by Jesus Christ that only small, scattered communities around the world still use.
It is full of troglodyte caves dating back to the first centuries of Christianity.
The clashes first erupted there on Wednesday, when Al-Nusra Front fighters and other Islamist rebels attacked a regime checkpoint at one entrance to the town.
The advance raised fears of attacks on churches or Christians in the town, but on Friday, the opposition Syrian National Coalition said rebels had withdrawn.
On Saturday, the Observatory said rebels were fighting pro-regime militias in western Maalula, and were also clashing with Syrian troops on its outskirts.