The Syrian civil war is far from over, and the participants aren’t shy to apply the quid pro quo principle to the ongoing fighting.

In 2016, Turkey was allowed to take control of Syria’s northern Aleppo province and the city of al-Bab in exchange for turning eastern Aleppo over to the troops of Syrian President Bashar al-Assad. Back then, the swap wasn’t blatantly obvious. But just days ago, on Jan. 20, the Turkish General Staff officially announced the launch of Operation Olive Branch in Afrin; later that day Syrian government forces conveniently seized the Abu al-Duhur air base in Idlib governorate — one of the largest airports and an important air base in northern Syria.

The very fact that the opposition groups surrendered the air base practically without a single shot, and that the Turkish military used its air force along with barreled and reactive artillery without any objections from Russia, proves that an agreement had been reached and that steps had been coordinated. Hours before Turkey’s Afrin operation, the Russian Defense Ministry relocated its military police and the center for reconciliation of the warring parties to the Tell Adjar area of the Tell Rifaat deconfliction zone “to prevent potential provocations, to exclude threats to the life and health of Russian servicemen.”

It appears Ankara had informed Moscow of the targets in advance, given that the Russian military was able to move 2 kilometers (1.2 miles) away from Menagh air base, which Turkey bombed soon after.