Russia’s financial markets were gripped by turmoil, with the rouble plunging nearly 30 percent against the dollar – after the European Union announced tough new punitive measures against Moscow,

Putin has played a major role in facilitating a peace accord between Azerbaijan and Armenia, hosting a meeting last November between Aliyev and Armenian Prime Minister Nikol Pashinyan.

In Ukraine’s second city, Kharkiv, authorities reported Russian military vehicles were on the move. Street clashes erupted in various districts. Pictures on social media showed two Russian vehicles on fire.

The city of 3 million endured a second night of shelling, with residents hunkering down in basement shelters and the city’s deep underground metro.

Among the strategic sites captured on the first day of the assault was the Chernobyl nuclear power station north of Kyiv, where staff still oversee the plant, though no reactors are in operation 36 years after the world’s worst nuclear accident.

Western countries denounced the Russian incursion, launched as the U.N. Security Council was debating the prospect of intervention, and pledged to introduce tough punitive measures on the Kremlin.

It was not immediately clear whether Moscow's forces had formally moved into the parts of Ukraine’s Donetsk and Luhansk region controlled by separatists – most analysts and Ukrainian officials have said that some Russian forces have long been informally established inside them.

It appears that Berdymukhamedov is taking full account of lessons in nearby Kazakhstan – plunged into deadly riots last month two years after a managed transfer of power.

The moves, announced after a meeting of Russia’s Security Council and a rambling, impassioned address by Putin to Russians, were not the full-fledged invasion predicted by many in the West after weeks of deployment by Russian troops on Ukraine’s borders.

Some Western leaders have in the past week warned of an imminent Russian invasion, with U.S. President Joe Biden saying he was “convinced” this would occur within days and Secretary of State Antony Blinken predicting a quick advance aimed at capturing the Ukrainian capital, Kyiv.