Interim opposition chief George Sabra was Tuesday working to secure the release of two bishops kidnapped in a north Syria village, a Greek official said, as a fresh wave of violence hit the country.
On the diplomatic front, US Secretary of State John Kerry was attending his first NATO foreign ministers in Brussels on Tuesday, with Syria the focus, while UN leader Ban Ki-moon urged an end to arms supplies to Syria's rival sides.
In Athens, Greek government spokesperson Simos Kedikoglou confirmed early Tuesday the kidnapping of Greek Orthodox bishop of Aleppo, Bolous Yazigi, and Syriac Orthodox bishop Yuhanna Ibrahim, first announced late Monday by Syria news agency SANA.
Greek Foreign Minister Dimitris Avramopoulos has spoken by phone to Sabra, newly-appointed head of the opposition Syrian National Coalition, who said he would act immediately to locate and liberate the bishops, the spokesman said.
SANA had reported the pair abducted while conducting "humanitarian operations" in Kafr Dael village in Syria's northern province of Aleppo.
"Terrorists intercepted the bishops' car in Kafr Dael village, took the driver out of the car and kidnapped the bishops," it said.
Christian residents of Aleppo reached by AFP said Ibrahim set out in his car to pick up Boulos Yazigi from the Bab al-Hawa crossing on the Turkish border, which is under rebel control.
The car was intercepted on the way back by gunmen who kidnapped the bishops and killed their driver, the residents said on condition of anonymity.
Kidnappings have become increasingly prevalent in Syria as law and order has broken down.
Activists and human rights groups say minority groups, including Christians, have been particularly vulnerable.
"Christians are sometimes more targeted by kidnappers since they have not organized themselves into militias under a tribal system," Antoine Audo, the Chaldean bishop of Aleppo, said in an interview with AFP earlier this year.
Christians account for about five percent of Syria's population and they have remained largely neutral or supportive of the regime since the outbreak of the uprising against the government in early 2011.
But the Syrian opposition also includes prominent Christian members, including Sabra, a long-time dissident who was named interim head of the main opposition Coalition on Monday.
The kidnapping of the bishops comes as rebel forces are being pushed back President Bashar al-Assad's loyalist troops, with the support of elite fighters from the Lebanese Shiite group Hezbollah in Al-Qusayr region of Homs province, according to the Syrian Observatory for Human Rights.
Hezbollah is a close ally of the Assad regime, but has defended any involvement of its forces in Syria as a bid to protect Lebanese citizens in a string of villages inside the war-torn country.
The Observatory on Monday reported that more than 100 people were found dead in a town near Damascus after a five-day operation to retake the town by regime troops.
"There are 101 martyrs who have been identified in Jdaidet Al-Fadl, which was taken completely by the army on Sunday. The victims are 10 women, three children and 88 men, including 24 rebels," Observatory director Rami Abdel Rahman told AFP.
Against that backdrop, Kerry on Sunday announced a doubling to $250 million of aid and non-lethal equipment for the rebels, urging others to follow suit amid sharp differences over the wisdom of providing arms, especially given the links of some Syrian groups with Al-Qaeda.
The issue was to be discussed in Brussels by the 28 NATO foreign ministers who were to have "have an exchange of information" about Syria and the other major issues of the day, a senior NATO diplomat said Monday.
NATO has no role in the conflict and alliance head Anders Fogh Rasmussen and other officials insist it requires a political solution.
On Monday, UN leader Ban Ki-moon appealed for an end to outside arms supplies to rival sides in the Syrian war but Arab League chief Nabil al-Arabi said that would not be possible.
Ban pleaded for a halt during talks with Arabi and Qatari Prime Minister Sheikh Hamad bin Jassem Al-Thani, whose country has been accused by Damascus of arming Syrian rebels.
"More arms would only mean more deaths and destruction," said UN spokesman Martin Nesirky.
But Arabi turned down the idea.
"If there is a political settlement or a beginning of a political settlement, that could happen but at this point I don't think it is possible," he said.