The United States has condemned Russia for striking the Western-backed militants in Syria and denied that it is cooperating with Moscow in this regard.
Speaking at a press conference in Rome, Italy, on Wednesday, US Defense Secretary Ashton Carter called the airstrikes against terrorists "a fundamental mistake".
"I have said before that we believed that Russia has the wrong strategy -- they continue to hit targets that are not ISIL. We believe this is a fundamental mistake," Carter claimed, using an acronym for the Daesh terrorist group.
"Despite what the Russians say we have not agreed to cooperate with Russia so long as they continue to pursue a mistaken strategy and hit these targets," he added.
Earlier in the day, the Russian Defense Ministry said it was considering proposals from the US to coordinate operations against ISIL terrorists.
"On the whole, these proposals could be put in place," defense Ministry spokesman Igor Konashenkov said.
He added that US and Russian military officials were discussing technical details on Wednesday.
"What we will do is continue basic, technical discussions on the professional safety procedures for our pilots flying above Syria," Carter said.
"That's it. We will keep the channel open because it's a matter of safety for our pilots," he added.
A new US intelligence assessment has found Russia has targeted militant groups backed by the Central Intelligence Agency (CIA) in Syria.
The assessment, shared by commanders on the ground, has led American officials to conclude that Russian warplanes have intentionally struck CIA-backed militants in a string of attacks running for days, the Wall Street Journal reported.
Meanwhile, US foreign policy expert Zbigniew Brzezinski, a strong supporter of the Obama administration, says the United States should retaliate if Russia does not stop bombing its assets in Syria.
Moscow's apparent decision to strike CIA-trained militants "at best" reflects "Russian military incompetence," and worst, "evidence of a dangerous desire to highlight American political impotence," Brzezinski, the national security adviser for former President Jimmy Carter, wrote in an article published by the Financial Times on Sunday.
He added that if Moscow continues to target these people, then Washington should retaliate against Russians.
Obama administration officials are debating how the United States can come to the aid of its proxy forces on the ground without risking a broader conflict, according to the Wall Street Journal.
US officials said Russia’s moves in Syria posed a direct challenge to the Obama administration’s foreign policy on the Middle East.