The Russian military says it has knocked out Ukraine's air defence assets and airbases.

Russian troops launched their anticipated attack on Ukraine on Thursday, as President Vladimir Putin cast aside international condemnation and sanctions, warning other countries that any attempt to interfere would lead to consequences you have never seen .

US Secretary of State Tony Blinken on Tuesday cancelled his scheduled meeting with his Russian counterpart Sergei Lavrov later this week in protest against what he said was the beginning of Russia's invasion of Ukraine.

Moscow: Russian lawmakers on Tuesday authorised President Vladimir Putin to use military force outside the country - a move that could presage a broader attack on Ukraine after the US said an invasion was already underway there.

Islamabad: Pakistan Prime Minister Imran Khan said on Tuesday that he would like to have a TV debate with his Indian counterpart Narendra Modi to resolve differences between the two neighbouring countries.

A long-feared Russian invasion of Ukraine appeared to be imminent Monday, if not already underway, with Russian President Vladimir Putin ordering forces into separatist regions of eastern Ukraine.