MOSCOW (AFP) - Washington's decision to provide military support for the Syrian rebels will hurt the chances of a new Russia-US peace initiative on the crisis, a top aide to Russian President Vladimir Putin said on Friday.

"Of course if the Americans truly decide and in reality provide more large-scale assistance to rebels, assistance to the opposition, it won't make the preparation of the international conference easier," Mr Putin's top foreign policy aide Yury Ushakov told reporters.