A group of nuns kidnapped by rebels in the Syrian town of Maalula in December were released early Monday thanks to Lebanese-Qatari mediation and handed to the Syrian authorities.

A monitoring group said the release was secured in exchange for some 150 women prisoners who were being held in Syria's regime jails.

The 13 nuns and three maids were kidnapped from the famed Christian hamlet of Maalula and taken to the nearby Syrian rebel town of Yabrud, where they were held by Al-Qaeda affiliate Al-Nusra Front.

They arrived at Jdeidet Yabus on the Syrian side of the border with Lebanon after an arduous nine-hour journey that took them from Yabrud into Lebanon, and then back into Syria.

An AFP journalist at Jdeidet Yabus said the nuns appeared exhausted, and that one of them had to be carried out of the vehicle transporting them.

Speaking to reporters at the border, one of the nuns said: "We want to thank God, who made it possible for us to be here now. We thank President Bashar Assad for being in contact with the emir of Qatar (Tamim Bin Hamad al-Thani).

"We will not forget the honest mediator, Abbas Ibrahim," she added, in reference to Lebanon's General Security agency director.

Seated as she spoke, the nun said all 16 hostages were treated "well" in captivity.

Al-Nusra Front "were giving us everything we asked for", she said.

"No one bothered us," she said, while denying earlier rumors their kidnappers had forced them to remove their crosses.

Meanwhile, the Syrian Observatory for Human Rights, a Britain-based monitoring group, said some 150 women who had been held in Syria's jails were on board four buses at the Lebanese-Syrian border, after being set free in exchange for the nuns.

"A woman and her four children who had been in jail were freed first and reached Yabrud," said Observatory director Rami Abdel Rahman, describing the initial release as "a gesture of goodwill" by the Syrian authorities.

"One hundred forty-nine other women prisoners are now with Lebanon's General Security agency after being freed from Syrian jails, in accordance with the deal," he told AFP.

Lebanon's official National News Agency quoted General Security chief Ibrahim, the key mediator, as saying: "The deal to secure the release of Maalula's nuns involved the release of more than 150 people in exchange."

Tens of thousands of people are being held in Syria's jails, where torture and ill-treatment are systematic, rights groups say.

Ibrahim led efforts to secure the release of the Maalula nuns along with Qatar's intelligence chief Ghanem al-Kubeissi, who arrived in Lebanon on Saturday.

Last year, Qatar and Lebanon's Ibrahim played a leading role in securing the release of a group of Lebanese Shiite pilgrims held by Syrian rebels in northern Syria.

Qatar has been a key backer of Syria's revolt.

The nuns had been kidnapped on Dec. 3 amid fighting for the ancient village of Maalula, which is currently in rebel hands.