The UN Security Council has declined to extend the Observer Mission for Syria today, effectively ending the mission as of Sunday when the current extension expires. The mission has been effectively suspended for months because of the civil war.
The observers were eventually sent to verify the ongoing ceasefire in the nation, but their mission was effectively meaningless after the Free Syrian Army (FSA) announced that they would no longer abide by the ceasefire and launched a new offensive.
Russia was the only nation that made a serious effort to extend the mission again, apparently fearing that the NATO nations on the council would use the end as an excuse to start pushing for a UN-backed invasion again.
With UN Special Envoy Kofi Annan having resigned there’s not much left for the monitoring mission to even attempt to do, and the nation is in a full-scale civil war with no sign of a new round of negotiation being pushed any time soon.