Syrian rebels on Wednesday seized an ancient town near the Jordan border that is a key government stronghold, ousting Syrian soldiers and allied militiamen from the region after four days of intense battles, opposition activists and rebels said.

There was no immediate comment from the government on the fall of Busra Sham, a town in southern Syria classified as a UNESCO World Heritage Site for its historic citadel, ruins and well-preserved Roman amphitheater. It was once the capital of the Roman province of Arabia and a stopover on caravan routes to Mecca, according to UNESCO.

Busra Sham had been in the hands of President Bashar Assad's troops throughout the four-year-old conflict and was considered to be a stronghold of pro-government forces in the southern province of Daraa.

The town's capture is a strategic gain because of its geographical location as well. Busra Sham is perched on highlands 6.2 miles from the Jordan border, overlooking the plains that spread out from the southern outskirts of Damascus.

"Today is a happy day, Busra al-Sham has been completely liberated," said Ahmad Masalma, an opposition activist in Daraa. He said some 10,000 rebels from various groups took part in the attack on the town, which began Saturday from three sides and ended at dawn Wednesday.

They included members of al-Qaeda's branch in Syria, the Nusra Front group.

He said Syrian government forces were holed up in the citadel in the last hours before they finally withdrew, adding that no major damage was done to the citadel or amphitheater.

The town's capture was also reported by the Local Coordination Committees and the Britain-based Syrian Observatory for Human Rights.