In a move that is unprecedented in the growing cooperation between the two nations, Turkey and Russia today announced that their warplanes launched a joint aerial attack on ISIS fighters in the Aleppo city of al-Bah, a city which Turkey has been sieging for over a month.

Russia had previously launched airstrikes in support of the Turkish siege, targeting ISIS forces around the periphery of the city. This is the first time, however, the two nations, which are co-sponsoring peace talks next week in Kazakhstan, are directly operating together in Syria.

That’s a huge turnaround from just 14 months ago, when Turkey shot down a Russian warplane over northern Syria, greatly increasing hostility between the two nations. In recent months they’ve been cooperating on brokering a ceasefire, planning peace talks, and fighting ISIS together.

The joint operations also dramatically undercut the Pentagon’s report of a single airstrike against al-Bab yesterday, which they presented as in support of Turkey, and which came after Turkey loudly criticized them for not sufficiently supporting the anti-ISIS operation.