KYIV, 24 Feb (AFP) -- Ukraine's Foreign Minister Dmytro Kuleba accused Russia's leader President Vladimir Putin of launching a "full-scale invasion" on Thursday (Feb 24), as explosions were heard in cities around the country.

"Putin has just launched a full-scale invasion of Ukraine. Peaceful Ukrainian cities are under strikes," Kuleba tweeted.

"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."

Meanwhile, Ukraine's ambassador to the United Nations implored the Security Council, chaired by Russia, to "do everything possible to stop the war" against his country.

"It is the responsibility of these bodies to stop the war," Sergiy Kyslytsya told a late-night meeting of the 15-member council which began shortly after Russian President Vladimir Putin announced a military operation in Ukraine.

Kyslytsya urged Russia's UN ambassador Vassily Nebenzia, which currently holds the rotating presidency of the council, to "call Putin, call (Foreign Minister Sergey) Lavrov to stop (the) aggression".