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Russian President Vladimir Putin recognised two breakaway regions in eastern Ukraine as independent on Monday (Feb 21) and ordered the Russian army to launch what Moscow called a peacekeeping operation into the area, a move that Washington said was part of Moscow's attempt to create a pretext for a further invasion of Ukraine.

Speaking at an emergency UN Security Council meeting on Tuesday, Ms Linda Thomas-Greenfield, US ambassador to the United Nations, described Russia's order to deploy "peacekeepers" in eastern Ukraine as 'nonsense'.

She said the consequences of Russia's actions will be dire across Ukraine, Europe and worldwide and that the humanitarian toll will expand significantly if Moscow invaded further.

Global affairs correspondent Jonathan Eyal discusses these developments.

Separately, the United States will announce new sanctions against Russia on Tuesday in response to Moscow's decision to recognise two breakaway regions of Ukraine as independent and send "peacekeeping" forces there, the White House said on Monday.

US President Joe Biden had earlier signed an executive order to prohibit trade and investment between US individuals and the two breakaway regions of eastern Ukraine.

Meanwhile, China's ambassador to the United Nations on Monday called all parties concerned in the Ukraine crisis to exercise restraint and avoid any action that might fuel tensions.

In very brief remarks at an emergency meeting of the UN Security Council over Ukraine, China's UN Ambassador Zhang Jun also said Beijing welcomed and encouraged every effort for a diplomatic solution to the crisis.

The Straits Times' US bureau chief Nirmal Ghosh weighs in on these reactions.

In other headlines, all employers in Singapore should not request medical certificates from workers who test positive for Covid-19 as the healthcare system continues to face stresses from rising infections amid the Omicron wave, Manpower Minister Tan See Leng said on Tuesday.

Employers and company HR departments should familiarise themselves with the prevailing Covid-19 health protocols and excuse employees from returning to their workplaces for the periods required, he told reporters at a doorstop interview.

And in this week's Invest segment, invest editor Tan Ooi Boon shares more about an almost scam victim who turned the tables on a fraudster.