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By Michelle Nichols
UNITED NATIONS, July 18 (Reuters) - International envoy Kofi Annan has asked the U.N. Security Council to delay a vote planned for later on Wednesday on a Western-backed resolution that threatens Syrian authorities with sanctions in a bid to end the 16-month conflict, Britain said.
"Joint Special Envoy Annan has asked to delay today's draft Syria resolution vote. With fellow co-sponsors (of the resolution) we're considering that request," the British U.N. mission said on Twitter.
The resolution, proposed by Britain, the United States, France and Germany, would extend a U.N. observer mission in Syria for 45 days and place Annan's peace plan under Chapter 7 of the U.N. Charter, which allows the 15-member Security Council to authorize actions ranging from diplomatic and economic sanctions to military intervention.
U.S. officials, however, have said they are talking about sanctions on Syria, not military intervention.
Russia has said it would block the Western-backed resolution because it does not believe it should be placed under Chapter 7. Russia and China have already twice vetoed U.N. Security Council resolutions designed to pressure Assad to halt the violence.
"After his Moscow meetings, Annan sees scope for compromise between Moscow and Western positions," said a Security Council diplomat, who did not want to be identified.
The Council has until Friday to decide the fate of the U.N. observer mission in Syria.
Russia, an ally of Syria, also has put forward a resolution to extend the U.N. mission for 90 days, but it does not contain a threat of sanctions. It was not clear when or if Russia planned to put its draft resolution to a vote.
After Council talks late on Tuesday on Russia's draft resolution, Britain's Deputy U.N. Ambassador Philip Parham said the Russians had not engaged at all in negotiations on the Western draft resolution.
"But we're making very clear that we're very open to their engagement and if they did we would welcome that," he said.
"We think (the Russian draft resolution is) inadequate ... because we think it would simply perpetuate the status quo which involves ever worsening violence," Parham said. (Reporting by Michelle Nichols; Editing by Vicki Allen and Paul Simao)