As the United States ramped up the pressure on Russia Thursday over its invasion of Ukraine, allies of Donald Trump blamed President Joe Biden for the crisis, accusing him of emboldening Moscow with a series of policy blunders.

Right-wing political figures and commentators dropped the long-standing custom of joining Democrats to speak with one voice in times of international crisis -- accusing the president of weakness and even rallying to Russian leader Vladimir Putin's side.

"Trump did the impossible and brought peace to the Middle East. Biden did the impossible and brought war to Europe," said Arizona congressman Paul Gosar, one of Trump's most loyal backers, who has been accused of ties with white nationalists.

"Vladimir Putin saw how weak President Biden has been as a world leader and took complete advantage of it. This will be yet another crisis to add to his failing resume," added Trump-endorsed Michigan representative Lisa McClain.

The barrage came just hours before Biden addressed the nation from the White House, announcing harsh new sanctions targeting Moscow including freezing assets of major Russian banks and stopping high-tech exports to the country.

Trump himself appeared on Fox News as explosions rang out in Kyiv to falsely blame the invasion on the "rigged election" that ended his tenure, and to accuse Biden of "probably sleeping right now."

But the former president, who has been making false accusations since his defeat to Biden that the 2020 election was stolen from him, appeared to have a poor grasp of the developments.

In a humiliating gaffe, he seemed to believe American troops had landed in Ukraine to fight Russians, and started berating the US military for not keeping the phantom operation secret before he was corrected.

'Weak and incompetent'

Trump -- who was impeached in 2019 after withholding military aid to Ukraine while pressuring it to investigate the Biden family -- had earlier said that Putin was "playing Biden like a drum," and praised his "genius."

Republicans in the House of Representatives attempted to humiliate Biden on Tuesday by tweeting a picture of him walking away from the podium after he announced initial sanctions against Russia.

The photo caption read: "This is what weakness on the world stage looks like."

Other leading figures in Trump's "America First" movement and key right-wing media voices have been blaming the violence on Biden's chaotic Afghanistan withdrawal last year and accusing him of prioritizing Ukraine's defense over tightening US border security.

Fox News prime-time host Tucker Carlson told viewers on Tuesday: "It may be worth asking yourself, since it is getting pretty serious, what is this really about? Why do I hate Putin so much?

"Has Putin ever called me a racist? Has he threatened to get me fired for disagreeing with him?"

Even the establishment Republicans, traditionally foreign policy hawks, sensed blood in the water ahead of November's crucial midterm elections, when Biden's Democrats are expected to suffer big losses in Congress.

Rick Scott, who runs the National Republican Senatorial Committee, called Biden a "failure" and said the Russian incursion was the result of America's enemies seeing a "weak and incompetent" US leader.

The party's moderate voices have been more circumspect.

The top Republicans on the House Foreign Affairs, Armed Services and Intelligence committees released a joint statement condemning Putin but refraining from criticizing Biden.

And former president George W. Bush focused on Putin's "authoritarian bullying," calling Russia's attack "the gravest security crisis on the European continent since World War II."