Syrian rebels have seized a convoy of UN peacekeepers near the Golan Heights and say they will hold them captive until President Bashar al-Assad's forces pull back from a rebel-held village which has seen heavy recent fighting.
The capture was announced in rebel videos posted on the Internet and confirmed on today by the United Nations in New York, which said about 20 peacekeepers had been detained.
The seizure, the most direct threat to UN personnel in the nearly two-year-old uprising against Mr Assad, came on the day that Britain said it would increase aid to the opposition forces and the Arab League gave a green light to member states to arm the rebels.
The regional Arab body also invited the opposition Syrian coalition to take Syria's seat at a League meeting in Doha later this month. Syria was suspended in November 2011 in response to its crackdown on protests which since spiralled into civil war.
The peacekeepers of the UNDOF mission have been monitoring a ceasefire line between Syria and the Israeli-occupied Golan Heights, captured by the Jewish state in a 1967 war, for nearly four decades.
Israel has warned that it will not "stand idle" as Syria's civil war spills over into the Golan region.
The United Nations in New York said its peacekeepers had been detained by around 30 fighters in the Golan Heights.
"The UN observers were on a regular supply mission and were stopped near Observation Post 58, which had sustained damage and was evacuated this past weekend following heavy combat in close proximity at Al Jamla," it said, referring to a village which saw fierce confrontations on Sunday.
It did not say the nationality of the observers but the Syrian Observatory for Human Rights monitoring group which is in contact with the rebel brigade said they were Filipino.
In one rebel video, a young man saying he was from the Martyrs of Yarmouk brigade stood surrounded by several rebel fighters with assault rifles in front of a two white armoured vehicles and a truck with UN markings.
"The command of the Martyrs of Yarmouk...is holding forces of the United Nations Disengagement Observer Force until the withdrawal of forces of the regime of Bashar al-Assad from the outskirts of the village of Jamla," the man, who was wearing civilian clothes, said.
At least five people could be seen sitting in the vehicles wearing UN light blue helmets and bullet-proof vests.
"If no withdrawal is made within 24 hours we will treat them as prisoners," he said, accusing them of collaborating with Mr Assad's forces to push the rebels out of Jamla.
Nearly two years since the uprising started, rebels are distrustful of a United Nations that they say has failed to support their cause.
Reuters