US and Russian fighter jets came within just 10 or 20 miles of each other in the skies over Syria on Saturday, it has emerged.
US military spokesman Col Steve Warren said that two combat aircraft flown by the US and two flown by Russia "entered the same battle space" and were in visual contact with each other, the BBC reported.
Col Warren also said that Russian planes had repeatedly broken air patrols, coming close to unmanned US aerial vehicles or drones, but Russia has not responded to those allegations.
The two powers are now set to hold a video conference to discuss ways of avoiding conflict while Russia carries out air strikes targeting Isis in Syria - a move the US has branded "reckless" and "wrongheaded".
US Secretary of Defence Ash Carter said he expected a deal "soon", but branded Russia's approach "strategically short-sighted".
"Even as we continue to disagree on Syria policy, we should be able to at least agree on making sure our airmen are as safe as possible," he added, as reported by the IB Times.
The discussions will form the third round of talks between the two nations, as the Russian defence ministry said it had "updated proposals on Syria for the US".
President Putin's forces began a campaign of strikes on 30 September, saying it was targeting jihadist groups after a request for help from Syrian President Bashar al-Assad.
But Russia has been accused of hitting non-militant targets - a claim Moscow denies.
