UNITED NATIONS - Negotiations on a resolution to extend a UN monitoring mission in Syria began on Thursday between a deeply divided UN Security Council with Russia saying it would not agree to a threat of sanctions in a bid to end the 16-month conflict.

The 15-member council must decide the future of the UN mission, known as UNSMIS, before July 20, when its 90-day mandate expires. UNSMIS was deployed to monitor a failed ceasefire as part of international envoy Kofi Annan's six-point peace plan.

Russia has proposed extending the mission for 90 days, but Britain, the United States, France and Germany countered with a draft resolution to extend the mission for just 45 days and place Annan's peace plan under Chapter 7 of the UN Charter.

Chapter 7 allows the council to authorize actions ranging from diplomatic and economic sanctions to military intervention. US officials have said they are talking about sanctions on Syria, not military intervention.