Russian forces invade Ukraine striking major cities

STORY: Russia has invaded Ukraine.

Explosions rang out in the capital Kyiv and other cities on Thursday.

They came after Russia's President ordered a military operation into Ukraine's east.

A Reuters witness heard blasts only minutes after President Vladimir Putin spoke on live TV.

There, he framed Russia’s move as an act of defense.

"I have decided to conduct a special military operation," said Putin, seated at a desk in the Kremlin next to a battery of telephones, with the Russian flag behind him. Its goal is to protect people who have been subjected to bullying and genocide... for the last eight years. And for this we will strive for the demilitarization and de-Nazification of Ukraine. "

It’s not clear just how big Russia’s operation might be, but it appeared to go beyond helping Russian-backed separatists in eastern Ukraine.

Russian forces fired missiles at several cities, and landed troops on Ukraine’s southern coast.

In the capital, explosions were heard and gunfire crackled near the main airport.

The U.S. and its allies have been quick to condemn Russia's actions.

President Joe Biden said he would meet the leaders of G7 to map out more severe measures against Russia, adding that: "Russia alone is responsible for the death and destruction this attack will bring."

The UN Secretary-General Antonio Guterres made a last-minute plea to Putin to stop the war "in the name of humanity.”

Biden has spoken to Ukraine's president, who announced that martial law would be introduced on all territories of the state.

Ukraine dismisses Russian claims of genocide, calling them invented.

It has also said Putin was looking for an artificial pretext to attack it.

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

Putin's actions came hours after a plea issued by pro-Russian separatists in eastern Ukraine to Moscow for help in stopping alleged aggression from Kyiv.

Claims the U.S. has dismissed as Russian propaganda and which Kyiv denies.