KRAMATORSK, Ukraine

Ukraine’s foreign minister vowed early Thursday to defend his country, saying Russian President Vladimir Putin “has just launched a full-scale invasion of Ukraine.”

“Peaceful Ukrainian cities are under strikes. This is a war of aggression. Ukraine will defend itself and will win. The world can and must stop Putin. The time to act is now,” Dmytro Kuleba said on Twitter.

Kuleba’s remarks came after Putin announced a special military operation early Thursday in eastern Ukraine’s Donbas region.

Following Putin’s announcement, large explosions were reported in Ukraine's capital Kyiv and city of Kramatorsk.