The UN Human Rights Council on Friday condemned the use of all foreign fighters in Syria's civil war, including Lebanese Hezbollah militants backing the government, but stopped short of calling for a halt to the flow of arms.

The Geneva forum adopted a resolution brought by Arab and Western powers, urging all parties to refrain from contributing to a further escalation of a conflict in which at least 93,000 people had been killed by the end of April.

Only Venezuela voted against the text, presented by Qatar on behalf of Britain, Kuwait, Saudi Arabia, Turkey, the United Arab Emirates, and the United States - which all back rebel forces. Thirty-seven states backed the motion. Nine abstained.

"Ecuador calls the Council's attention to that fact that the main proponents of this draft resolution are the ones contributing to continuation of violence by providing arms to opposition groups, thus contributing to the escalation of violence," Ecuador's Ambassador Luis Gallego Chiriboga said.

Other Latin American and Asian countries, including Brazil and Pakistan, voiced concerns that the Council had failed to use stronger language to denounce the weapons pouring into Syria.

"If we fail to condemn the transfer of arms in the resolution it is tantamount to adding fuel to the fire," Costa Rica's deputy ambassador Christian Guillermet-Fernandez said.

The heated debate was held a day after the United States said it would now arm rebels, having obtained what it said was proof the Syrian government used chemical weapons against fighters trying to overthrow President Bashar Assad.

 Venezuela's representative, Felix Pena Ramos, referring to the U.S. accusation on the Syrian government's use of chemical weapons, said: "I am sure these are same people who confirmed there were weapons of mass destruction in Iraq."

Syria and its ally Russia rejected the text as unbalanced and counterproductive as efforts were being made to convene an international peace conference.

"It turns a blind eye to the presence of jihadists that come from more than 40 countries," Syrian Ambassador Faysal Khabbaz Hamoui said. "Certain countries that sponsored the resolution have financed, trained and supported them."

Russia, whose delegation has observer status and cannot vote, regretted that the United States was one of the initiators of the text despite their joint efforts to convene peace talks.

"The latest one-sided resolution on Syria talks about Hezbollah, but they don't seem to be worried about 1,000 highly-paid and heavily armed rebel groups," said Russian second secretary Roman Kashaev.