Former US President Donald Trump says "the incompetence" of the Biden administration could lead to an escalation of the Ukraine crisis.

There are "incompetent people running things," Trump told a rally of his supporters in Greenwood, Nebraska on Sunday, warning them that the situation in Ukraine was "a very dangerous thing [... that] could be a world war."

Trump lambasted President Joe Biden, saying his performance was "an unmatched an unmitigated failure," reiterating that Biden had done more damage in 16 months of the presidency than the five worst Presidents in US history combined.

According to Trump, Biden was "embarrassing" the United States, costing it its respect from world leaders, including Russian President Vladimir Putin.

Trump claimed that Putin "is throwing the word ['nuclear'] around all the time because he doesn't respect our leadership."

However, Trump's assertions fall flat because Russian Foreign Minister Sergey Lavrov has repeatedly stressed that Russia was not threatening anyone with nuclear war; the West and Ukraine have been persistently "playing with the words 'nuclear war'."

Trump said other presidents were not returning Biden's phone calls, explaining that they wanted "nothing to do with him other than tak[ing] advantage of US." He also stressed that Biden should be "taking a cognitive test and releasing results for the entire world to see."

Citing record inflation and rising prices, Trump said the Biden administration was trying to shift blame and accusing Putin of being responsible for the debacle the US was undergoing. "Let's blame Putin. Why the hell not," Trump said mockingly.

The US lost its dominant position in the energy sector, the former President stressed, highlighting how Washington was trying to strike deals with Iran, Venezuela, Russia, and OPEC to lift it out of its crisis.

The Democrats and the incumbent US administration are the biggest threat to the country, Trump stressed, instead of external issues, such as the Ukraine crisis. He also underlined that the upcoming midterm elections were "the most important midterm in US history," urging his supporters to take to the polls and vote. 

In a Washington Post-ABC News poll conducted in late April, Biden's overall disapproval rate was around 52%, while 47% of Americans disapproved of his handling of the Ukraine crisis in particular, with only 42% approving.

#US President #JoeBiden spoke at the first White House Correspondents' Dinner since 2019, mocking his own low approval ratings and joking about what he called the "horrible plague" of predecessor Donald #Trump.#CorrespondentsDinner pic.twitter.com/1Dwchmfwh1

— Al Mayadeen English (@MayadeenEnglish) May 1, 2022

CNN reported earlier in April that Biden's approval rating hit the lowest point of any president before him after a year and three months in office.