By Louis Charbonneau

UNITED NATIONS (Reuters) - European U.N. Security Council members softened a draft resolution condemning Syria's six-month crackdown on anti-government protests but Russia said on Thursday that it could not support the new text.

The four European members of the council had hoped to put the draft resolution to a vote on Friday. The United States is expected to support it, envoys said, despite its disappointment about compromises made in an attempt to woo Russia, China, Brazil, India and South Africa -- the "BRICS" nations.

The latest attempt to bridge the wide differences between those five nations on the one hand and the United States and European members of the council on the other comes after months of resistance by the BRICS to any tough action on Syria, whose clampdown the U.N. says has killed over 2,700 civilians.

But the 15-nation council was still deadlocked after a closed-door meeting on the new draft, dimming prospects for an early vote on it. Russian U.N. Ambassador Vitaly Churkin said the revisions did not go far enough to satisfy Moscow.

"I'm not optimistic," Churkin said before the meeting. Asked if the Europeans had sufficiently taken Russian concerns into consideration, he said: "No, they didn't."

After the meeting Churkin explained that Russia opposed any mention of the possibility of future U.N. sanctions against Syria in the draft resolution, language that German Ambassador Peter Wittig said was non-negotiable for the Europeans.

"We want to keep the essential message of that resolution, and that is if the repression and the violence doesn't stop, there will be further measures," Wittig said.

Indian Ambassador Hardeep Signh Puri said a Friday vote on the resolution was unlikely, though he said council members were still working to find a common position.

U.S. WANTS 'MORE TEETH'

It was not clear what the other BRICS nations thought, although Western diplomats said Russia and India were proving the most difficult to win over.

The Europeans were planning to circulate another amended draft to the council later on Thursday so that members could discuss it on Friday, council diplomats said.

The United States, whose ambassador in Damascus was the target of stone-throwing supporters of President Bashar al-Assad on Thursday, has not participated in the drafting process. One diplomat said the U.S. delegation had hoped the council could approve something with "more teeth."

The latest version of the resolution showed that drafters Britain, France, Germany and Portugal had deleted a reference to U.N. human rights chief Navi Pillay's recommendation that the council consider referring the Syrian government's crackdown to the International Criminal Court in The Hague.

Churkin said one of his biggest problems with the draft was its penultimate paragraph, which says the council would "review Syria's implementation of this resolution within 30 days, and, in the event that Syria has not complied ... to consider the adoption of targeted measures, including sanctions."

Russia, however, does not object to the resolution's call for an immediate end to the violence and the swift release of political prisoners. That demand was included in a competing Russian draft resolution.

The EU draft also added language reminiscent of the Russian text that suggested the opposition in Syria shares the blame for six months of violence.

The idea that the opposition is equally responsible for the violence as Assad's government is a view that Western nations have so far vehemently rejected.

(Editing by Doina Chiacu)