The US administration's decision to drop its recognition of the Syrian National Council (SNC) as the leading Syrian opposition group and propose creating a new umbrella organisation surprised and puzzled close allies.
The move is sure to have repercussions for Arab League-sponsored meetings that start today in Qatar, at which the SNC planned to elect new leadership and reorganise its structure.
The US government gave no advance notice of its intention to renounce the council as the lead umbrella group, diplomats of three countries said.
They said their governments learned about the initiative from news accounts.
Diplomats criticised US Secretary of State Hillary Rodham Clinton for using what they called inappropriate language in describing the council as made up of people who have not been in Syria for decades; many of its members, the diplomats said, left the country only after the uprising against President Bashar al- Assad began 19 months ago.
"We have recommended names and organisations that we believe should be included in any leadership structure," Clinton said on Wednesday in announcing the administration's break with the council.
Unusually, the move was made public in a statement to reporters who were travelling with her, after a meeting with the president of Croatia. "We've made it clear that the SNC can no longer be viewed as the visible leader of the opposition."
A Western diplomat said: "We were a bit surprised, especially when they said they'd suggested the names for the new body.
"Syrians will say the Americans are imposing the names. And I am not sure the Americans would propose the right people."
He called it "a bit too harsh" for Washington "to throw away" the executive committee and the whole 310-member general assembly of the SNC. "We know they were not representing the entire opposition, but you can't say they did nothing. They still have a role to play."
The SNC lashed out at Washington, saying any "discussions aimed at passing over the Syrian National Council or at creating new bodies to replace it are an attempt to undermine the Syrian revolution by sowing the seeds of division".
Meanwhile, a Syrian rights group released videos of pro-regime fighters apparently killing prisoners and cutting ears from bodies, after a video showing rebels executing soldiers raised international concerns.
The Syrian Observatory for Human Rights, a Britain-based watchdog, said it had received the videos after the images of rebels appearing to beat and kill captured troops sparked an international uproar.
"These videos were provided by activists following the broadcast the day before yesterday of a video showing atrocities committed by the rebels," said the Observatory's director, Rami Abdel Rahman.
"The regime has committed war crimes and crimes against humanity since the first day of the revolution, but these crimes cannot in any way justify crimes by the other side," he said.
One video, filmed in February, shows fighters, some in civilian clothes and some in uniforms, firing automatic weapons at a group of men lying on the ground whom they say are rebels.