Russian President Vladimir Putin late Thursday said he was ready to coordinate strikes against the so-called Islamic State with the United States and its allies but warned that acts like the Turkish downing of a Russian jet could destroy any chance of collaboration, according to the Washington Post.

After talks with French President François Hollande at the Kremlin, Putin said, “We are ready to cooperate with the coalition which is led by the United States.”

It was the most forthright commitment to a joint effort between Russia and the West since Moscow’s seizure of Crimea from Ukraine in 2014.

But it was far from the declaration of a new grand coalition in Syria, potentially under United Nations auspices rather than American leadership, that Putin has proposed. The deep disagreement between Russia and the West over the future of embattled Syrian President Bashar al-Assad has not been put aside.

Hollande said France was ready to fight alongside Russia but added, “Of course, Assad cannot play any role in the future of this country.”

But cooperation between Russian and Western forces operating in and over Syria faces another significant hurdle: the growing animosity between Russia and Turkey. Russian officials on Thursday promised broad sanctions against Turkey, cutting joint investment projects and banning many Turkish companies from working in Russia.

Sources: MENA