U.S. Secretary of State John Kerry phoned Russian Foreign Minister Sergei Lavrov for the third time in the past ten days to discuss the situation in Syria. He warned Lavrov that Russia’s support of beleaguered President Bashar al-Assad “will only prolong the Syrian conflict.”

However, Russia’s presence in Syria has been ongoing for years, despite intense media attention the past few weeks. Russian President Vladimir Putin has supported Assad since civil war broke out in his nation four years ago.

“Secretary Kerry made clear that Russia’s continued support for President Assad risks exacerbating and extending the conflict, and undermining our shared goal of fighting extremism,” the Department wrote in a statement.

Russia caught international criticism after Syrian television broadcast footage of Russian troops alongside Syrian troops earlier this month. But evidence through the years proved Russian equipment had already been shipped to Syria, including in an Islamic State (ISIS/ISIL) video.

In August, Lavrov traveled across the Middle East, where he urged leaders to accept Assad as a partner in the fight against radical Islamic groups like ISIS. Turkish Foreign Minister Mevlüt Çavuşoğlu turned him down, along with Saudi Arabian Foreign Minister Adel al-Jubeir. Kerry told Lavrov again that Assad can never be a viable part of a coalition against the sadistic group.

“Secretary Kerry also reaffirmed the US commitment to fight ISIL with a coalition of more than 60 countries, of which Assad could never be a credible member, and emphasised the US would welcome a constructive Russian role in counter-ISIL efforts,” continued the Department. “The secretary stressed that there is no military solution to the overall conflict in Syria, which can only be resolved by a political transition away from Assad.”

Last Friday, Russia warned the U.S. that not cooperating with Russia on the Syrian crisis may result in “unintended incidents.” The Mediterranean island of Cyprus confirmed the Russian government “informed it of live-fire naval exercises to be conducted off Syria.” The U.S. and Russian forces in Syria are not speaking to each other, even though both admit radical jihadist groups like the Islamic State (ISIS/ISIL) are their common enemy.

“Coalition forces are focused on conducting counter-ISIL operations, and so to my knowledge there is no military-to-military contact at this point,” explained Air Force Col. Patrick Ryder, adding:

We’re keeping an eye on the Russian situation there, but right now again there’s really no deconfliction to do. I think what you’re getting at is: [deconfliction] in the event there’s some type of Russian military or air activity, but again, I’m not going to speculate or talk about hypotheticals. Certainly, we have very professional air forces, and the coalition is going to ensure the safety of those forces where we operate.

President Barack Obama claimed Russian movements will not change “strategy in countering Islamic State fighters.”

“But we are going to be engaging Russia to let them know that you can’t continue to double-down on a strategy that is doomed to failure,” he announced.