Turkey's Foreign Ministry called on citizens in Ukraine to remain in their homes or safe places after Russia launched a military operation against the country.

The ministry said assistance will be provided to citizens wanting to leave Ukraine.

Earlier on Thursday, flag carrier Turkish Airlines (THY) said it canceled all flights to Ukraine on Feb. 24 because of the closure of Ukrainian air space.

President Vladimir Putin officially ordered the deployment of Russia's military in the eastern Ukrainian regions of Donetsk and Luhansk in a televised address early Thursday.

"I have decided to carry out a special military operation," Putin said.

About an hour later, Ukrainian President Volodymyr Zelenskyy declared a state of war for the entire country, while Ukrainian Foreign Minister Dmytro Kuleba said that strikes were already hitting Ukrainian cities.

Russia had launched a "full-scale invasion of Ukraine," Kuleba tweeted. "This is a war of aggression. Ukraine will defend itself and will win. The world can and must stop Putin," he added.