Secretary of Defense Ash Carter said Wednesday that, by supporting Syrian President Bashar Assad, Russia's activities in the region are the equivalent of "pouring gasoline on a fire."
His comments come on the heels of news that Russia has begun carrying out strategic airstrikes in Syria on Wednesday. A Russian general, on behalf of a coalition being headed by Moscow, gave roughly an hour's warning to the U.S. to steer clear of the country's airspace as its warplanes joined in the fight against ISIS.
The U.S. State Department said Moscow's request would be ignored, adding that American jets would continue to fly missions as part of a separate air campaign to root out the militants.
"Fighting ISIL without pursuing a parallel political transition only risks escalating civil war in Syria," Carter said using an alternative reference to ISIS and echoing the administration's assertion that any steps toward ridding the region of the terrorist group's influence must steer clear of backing Assad's regime.
Carter said there is an inherent contrast in Russia carrying out airstrikes in an area of Syria where ISIS forces are not believed to be present.
"There is a logical contradiction in the Russian position and now its actions in Syria," Carter said.
He added "the Russian approach is doomed to fail."
Russian Foreign Minister Sergei Lavrov had a fiery response to Carter's comments: "Don't listen to the Pentagon about Russian strikes."
The U.S. and Russia diverge on Assad's leadership. The White House has underscored the need for a political transition in Syria stressing that Assad must go, while Putin has put Assad up as the only option to defeat ISIS.
Secretary of State John Kerry quickly questioned Moscow's actions Wednesday and asked during a U.N. General Assembly meeting in New York whether Russia's intentions in Syria "reflects a genuine commitment to defeating" ISIS. He said those efforts cannot be confused with supporting Assad, who is in a struggle for power with both ISIS and rebel factions.
Foreign policy experts say Moscow is seizing on a perceived American vulnerability in addressing the Syrian conflict and making a power play in the war-torn region.
In his address to the United Nations General Assembly on Monday, Putin called for an "international coalition against terrorism" which would include Syria. Putin also defended his efforts to prop up Assad as the only way to curtail ISIS and stem the overwhelming flow of refugees.
Putin's endorsement of an international coalition helps put him in a position to help prop up Assad, an ally in the region and could help Moscow play a pivotal role in choosing the Syrian leader's successor should he leave office, said David Rothkopf, a former Clinton administration official and editor of Foreign Policy Group, a collection of foreign policy publications.
"It's a deliberately calculated step by Putin to say Obama and the West today aren't doing enough and we should step up and fill the void," Rothkopf said.
Putin's comments which included accusing the U.S. of a "policy based on overconfidence" were a direct retort to Obama's remarks earlier in the day when he called Assad a "tyrant" and a "dictator" who should be removed from power.
"When a dictator slaughters tens of thousands of his own people it's not a matter of one nation's internal affairs," Obama said.
Relations between the U.S. and Russia have fallen to near Cold War-level lows amid disagreements over Russia's annexation of portions of Ukraine and growing Russian military presence near the Syrian port city of Latakia. And, during separate addresses on Monday, the two leaders offered sharp retorts countering what each sees as misguided efforts in dealing with the growing conflict in Syria.
Putin's derision during an interview on "60 Minutes" of U.S. struggles to train and retain Syrian rebels — a $500 million program has been widely criticized in the media and on the Hill — is an added bit of sting.
Meanwhile, Putin's moves have left the impression that the U.S. is scrambling as Russia challenges American influence in the region, foreign policy experts said.