WASHINGTON

The US is sending approximately 7,000 more troops to Europe amid a military intervention in Ukraine by Russia, a senior defense official said Thursday.

Secretary of Defense Lloyd Austin ordered the deployment at the direction of President Joe Biden.

"This would comprise an armored brigade combat team with associated capabilities and enablers. They will deploy to Germany to reassure NATO Allies, deter Russian aggression and be prepared to support a range of requirements in the region. We expect them to depart in the coming days," said the official.

Russian President Vladimir Putin announced a military intervention in Ukraine early Thursday, days after recognizing two breakaway enclaves in eastern Ukraine, drawing international condemnation and vows of tougher sanctions on Moscow.

Explosions were reported in several Ukrainian cities, including the capital, Kyiv, and tanks reportedly crossed the border from Belarus into Ukraine.

In recent weeks, US officials accused Russia of amassing more than 150,000 troops around Ukraine to launch a military attack but Moscow repeatedly denied any intent to launch an invasion.

*Kasim Ileri contributed to the story