Russia invades Ukraine in 'grave moment' for Europe

STORY: Russian forces invaded Ukraine by land, air and sea on Thursday (February 24), in the biggest attack by one state against another in Europe since World War Two.

Russian missiles rained down on Ukrainian cities and Ukraine reported columns of troops pouring across the borders into the east.

Russian troops landed by sea at the port cities of Odessa and Mariupol in the south.

Explosions were heard before dawn in the capital Kyiv. Gunfire rattled, sirens blared, and the highway out of the city choked with traffic as residents fled.

Black smoke rose over the headquarters of Ukraine's military intelligence.

The assault followed weeks of fruitless diplomatic efforts by Western leaders to avert war and realized their worst fears about Russian President Vladimir Putin's ambitions.

U.S. President Joe Biden said he would meet the leaders of G7 to map out more severe measures against Russia, holding it responsible for, quote, "the death and destruction this attack will bring."

Ukraine's President Volodymyr Zelenskiy called on Ukrainians to defend the country on the streets, and said arms would be given to anyone prepared to fight.

"We are already handing out weapons, and will hand them out to defend our country to everyone who wants and has the capacity to defend our sovereignty. The future of Ukraine depends on every citizen."

Putin framed the invasion as an act of defense to protect people, including Russian citizens, subjected to "genocide" in Ukraine - an accusation the West calls absurd propaganda and Ukraine dismisses, saying Putin was looking for an artificial pretext to attack it.

Russia has been demanding an end to NATO’s eastward expansion.

NATO Secretary General, Jens Stoltenberg, condemned the invasion as a 'grave moment for the security of Europe.'

“This is a deliberate, cold-blooded and long-planned invasion. Despite its litany of lies, denials and disinformation, the Kremlin’s intentions are clear for the world to see."

Initial reports of casualties were unconfirmed. Ukraine reported at least eight people killed by Russian shelling and three border guards killed in the southern Kherson region.

Ukraine's military said it had destroyed four Russian tanks on a road near Kharkiv, killed scores of troops near a town in Luhansk region and downed six Russian warplanes in the east - all of which Russia denied.

EU foreign affairs chief Josep Borrell called these among the 'darkest hours' of Europe since the last world war.