Unfazed by tough Western sanctions, President Vladimir Putin said on Thursday that he decided to launch a "special military operation" aimed at the "demilitarisation and denazification" of Ukraine and also bring to justice those who committed numerous crimes against peaceful people, including Russian nationals.

"People's republics of Donbass approached Russia with a request for help. In connection therewith, I made the decision to hold a special military operation, Putin said in a special television address.

He said the goal of the military operation is to protect the people that are subjected to abuse, genocide from the Kiev regime for eight years, and to this end we will seek to demilitarise and denazify Ukraine and put to justice those that committed numerous bloody crimes against peaceful people, including Russian nationals.

Justice and truth are on Russia's side, Putin was quoted as saying by state-run TASS news agency.

"Forces are always needed but they can be of different quality," he said. "And we know the real strength is in justice and truth that are on our side."

Putin said all the Ukrainian servicemen that will refuse to perform unlawful orders of Kiev and disarm will be able to freely leave the zone of military activities.

"Do not perform their unlawful orders! I urge you to immediately disarm and go home. To make it clear: all servicemen of the Ukrainian army that will fulfill this demand will be able to freely leave the zone of combat action and return to their families," Putin said.

"All the responsibility for possible bloodshed will be entirely on the conscience of the regime ruling in the territory of Ukraine," he added.

Meanwhile, the Russian Ministry of Defence has said that it used precision weapons to neutralise Ukrainian air forces and air defences, as well as military infrastructure.

"Ukrainian military infrastructure, air defence facilities, military airfields, and air forces are being neutralised by high-precision weapons", the ministry said in a statement.

The ministry stressed that the Russian military is not attacking Ukrainian cities, so there are no threats to the civilian population.

President Putin on Monday signed decrees to recognise Ukraine's regions of Donetsk and Luhansk People's Republics as independent , escalating the tension in the region. He also ordered Russian troops into eastern Ukraine in what the Kremlin called a "peacekeeping" mission in the Moscow-backed regions.

On Thursday, Putin announced the launch of a military operation in eastern Ukraine just as the UN Security Council was holding an emergency meeting on the crisis.

The US-led West, which has already imposed punitive sanctions on Russia, has warned Moscow that it would face severe consequences for its actions in Ukraine.