Turkey has closed its airspace to Russian civilian and military planes flying to Syria, Foreign Minister Mevlut Cavusoglu was quoted as saying Saturday by local media.

The announcement marks one of the strongest responses to date by Turkey, which has cultivated close ties with Moscow despite being a member of the NATO defence alliance, to Russia's two-month military assault on Ukraine.

"We closed the airspace to Russia's military planes -- and even civilian ones -- flying to Syria. They had until April, and we asked in March," Turkish media quoted Cavusoglu as saying.

Cavusoglu said he conveyed the decision to his Russian counterpart Sergei Lavrov, who then relayed it to President Vladimir Putin.

"One or two days later, they said: Putin has issued an order, we will not fly anymore," Cavusoglu was quoted as telling Turkish reporters aboard his plane to Uruguay.

Cavusoglu added that the ban would stay in place for three months.

There was no immediate response to Turkey's announcement from Russia, which together with Iran has been a crucial supporter of Syrian President Bashar al-Assad during the war-torn country's civil war.