Russia and the US have signed a deal that they hope will avoid clashes between their air forces in the skies over Syria, officials from both countries stated.
Russian began air strikes in Syria on 30 September, saying it was targeting Islamic State (IS) militants.
Last week, the US said both countries' planes "entered the same battle space" and came within miles of each other.
Officials had been seeking an agreement since late September.
Pentagon spokesman Peter Cook has stated to media that the text of the deal would remain secret at Moscow's request, but that it laid out means for both sides to communicate and establish a hotline on the ground.
The two countries would not, however, share intelligence on their targets, he has told.