Five Russian planes and one helicopter have been shot down in Ukraine's Luhansk region, the country's military claimed on Thursday. 

Luhansk is one of the separatist regions in Ukraine that was recognised as independent by Russia earlier this week.

“According to the Joint Forces Command, today, February 24, in the area of the Joint Forces operation, five planes and a helicopter of the aggressors were shot down," Ukraine’s army general staff was quoted as saying by news agency AFP.

Russia's military has also claimed that the Ukrainian air defence has been neutralised hours after it started launching attacks on major cities. 

These developments come as Russian President Vladimir Putin launched a military operation in Ukraine on Thursday with explosions heard across the country and its foreign minister warning a "full-scale invasion" was underway.

Weeks of intense diplomacy and the imposition of Western sanctions on Russia failed to deter Putin, who had massed between 150,000 and 200,000 troops along the borders of Ukraine.

"I have made the decision of a military operation," Putin said in a surprise television announcement that triggered immediate condemnation from US President Joe Biden and other Western leaders, and sent global financial markets into turmoil.

As per reports, Russia launched artillery attack along Ukraine's northern border with Russia and Belarus. Ukrainian forces were returning fire.

Explosions were heard in Kyiv, Dnipro, Zaporizhia, Kharkiv, Kramatorsk, Mariupol and Odessa. The Russian forces also confirmed that it is conducting precision strikes to target Ukrainian military establishments and said that there are no threats to civilian populations.

Meanwhile, Ukraine said that Russia used ballistic missiles to attack the military establishments.

News agency MSNBC reported citing Ukrainian police officials from the city of Odessa that six people died and seven were wounded and nineteen were missing due to the bombings by Russians.

US President Joe Biden has since condemned Putin's order of invasion, noting that he would be coordinating with Nato allies to respond to Russia's aggression.