New Delhi, Feb 24 (IANS): Asian markets and US stock futures plunged on Thursday as Russian President Vladimir Putin announced a military operation in the Donbas region of Ukraine, CNN reported.

Hong Kong's Hang Seng Index declined 3.2 per cent, while South Korea's Kospi dropped 2.7 per cent. Japan's Nikkei 225 lost 2.4 per cent after coming back from a holiday and China's Shanghai Composite moved 0.9 per cent lower.

US stocks futures also tumbled. Dow futures were down as much as 780 points, or 2.4 per cent. S&P 500 and Nasdaq futures were down 2.3 per cent and 2.8 per cent, respectively.

The Moscow Exchange announced on Thursday it had suspended trading on all of its markets until further notice, CNN reported.

The Russian ruble plummeted nearly 10 per cent against the US dollar, trading at 89.59 per dollar.

Putin's announcement came as concerns mounted of an imminent full-scale Russian invasion.

Ukrainian President Volodymyr Zelensky said in an emotional speech early Thursday that the Russian leadership had approved military action in Ukraine and vowed the country would defend itself, CNN reported.

"Geopolitical risks remain at the forefront, weighing on risk assets as heightened uncertainty over Ukraine continue to keep market participants on edge," wrote Yeap Jun Rong, a market strategist for IG Group, in a note on Thursday.

He added that Putin is probably "willing to weather the economic impact of sanctions, which may bring into question on what the Western powers can do to hold off an invasion".

Brent crude, the world benchmark, climbed above $100 a barrel for the first time since 2014. US crude jumped 4.8 per cent to $96.55 a barrel.