THE UNITED STATES DECLARES THE PUTIN NUCLEAR ORDER 'UNACCEPTABLE,' AND CONSIDERES ADDITIONAL SANCTIONS.

On Sunday, the US and NATO slammed Russian President Vladimir Putin's decision to put his nuclear forces on high alert as dangerous and unacceptable, while the White House stated that fresh penalties against Russia's energy sector are not ruled out.

Putin cited "aggressive words" from NATO members and extensive sanctions imposed by Western nations in issuing the order to prepare Russia's nuclear weapons for higher readiness for launch.

Linda Thomas-Greenfield, the United States' ambassador to the United Nations, told CBS's "Face the Nation" programme that Putin's actions have worsened the crisis and are "unacceptable."

"We're continuing to look at additional and even stronger actions against the Russians," Thomas-Greenfield added.

Putin's nuclear order was also seen as an escalation by a senior US defence official, who said it was "putting in play forces that, if there's a miscalculation, could make things much, much more hazardous."

The US is attempting to ascertain what Putin's instruction means "in concrete terms," according to the official, who spoke on the condition of anonymity.

NATO Secretary-General Jens Stoltenberg termed Putin's nuclear command "aggressive" and "irresponsible" on CNN's "State of the Union" programme.

Putin, according to White House Press Secretary Jen Psaki, was reacting to a fictitious threat.

"This is something we've seen him do before. "At no point has Russia been threatened by NATO, nor has Russia been threatened by Ukraine," Psaki said on ABC's "This Week."

APPEALS FROM THE UNITED STATES TO CHINA

According to Psaki, the US has not ruled out sanctions against Russia's energy industry.

"However, we also want to make sure we're minimising the impact on the global economy and doing it in a coordinated manner," she added.

The Biden administration has taken steps to limit the risk that its sanctions may raise already-high gas and energy costs in the United States. It made an exception for energy-related activities when it slapped sanctions against key Russian banks on Thursday.

Psaki encouraged China to express a formal denunciation of Russia's invasion in the administration's most urgent public appeal to the Communist country yet.

"This is not the time to be a spectator," Psaki said on MSNBC. "Now is the time to speak out against President Putin's conduct and Russia's invasion of a sovereign country."

On Friday, Chinese Foreign Minister Wang Yi stated that China respects the sovereignty of all countries, including Ukraine's, but that Russia's worries over NATO's eastward expansion should be addressed correctly.

Meanwhile, Republicans in Congress continued to lash out at Putin, indicating that for the time being, both parties are broadly supporting the Biden administration's efforts.

Following Russian President Vladimir Putin's nuclear command, Representative Kevin McCarthy, the senior Republican in the House of Representatives, told Fox News Channel that "no government in the world should stand with Putin."

Senator Mitt Romney, a former Republican presidential candidate, described Putin as "a little, wicked feral-eyed man who is attempting to create the globe in the image of Russia being an empire once again – and that's not going to happen" on CNN.

On Sunday, US Secretary of State Antony Blinken announced an additional $54 million in humanitarian relief for Ukrainians affected by the invasion, on top of the $350 million the US had already donated last week.

In a statement, Blinken added, "This includes the provision of food, safe drinking water, shelter, emergency health care, winterization, and protection."

Senator Chuck Schumer, the Senate's majority leader, said the Senate would consider the White House's request for an additional $6.4 billion in help in the coming days.