As world leaders united to condemn the Russian president and impose sweeping sanctions on his government and oligarch allies, Mr Trump doubled down on earlier comments about Mr Putin.

“Yesterday reporters asked me if I thought President Putin is smart. I said of course he’s smart,” he told the crowd at the annual Conservative Political Action Conference in Orlando, Florida.

“The problem isn’t Putin is smart — which of course he is smart — it’s that our leaders are dumb,” he said, adding that Nato nations “are not so smart, they are looking the opposite of smart.”

Mr Trump went on to blame the Biden administration for Russia’s decision to invade its neighbour, an attack that was justified by Mr Putin’s false claims that Ukraine was run by “drug-addicted, neo-Nazi” leaders.

“Under our leadership the world was a peaceful place because America was strong and the perception of our country was perhaps like it had never been before: powerful, cunning and smart. We were a smart country. Now we are a stupid country,” Mr Trump said.

Mr Trump called the Russian invasion of Ukraine an “atrocity” in the wide-ranging speech, which touched upon the unfolding crisis in between false claims about the 2020 election and complaints about his treatment by the media. 

“The Russian attack on Ukraine is appalling, an outrage and an atrocity that should have never been allowed to occur. We are praying for the proud people of Ukraine, God bless them all,” he said.

“When you have a weak president who is not respected by other nations you have a very chaotic world. The world hasn’t been this chaotic since World War Two,” he said.

He added that Mr Putin “is playing Biden like a drum and it’s not a pretty thing to watch.” He speculated that the Russian president made his decision to attack Ukraine “only after watching the pathetic withdrawal from Afghanistan.”

Mr Trump’s comments follow a shift in tone from many Republicans with regards to Mr Putin following the unprecedented military action that brought war to Europe.

More than 150,000 Ukrainians have fled to Poland, Moldova and other neighbouring countries since the invasion began and that number could reach 4 million if fighting escalates further, according to the United Nations.

The Biden administration on Saturday pledged an additional $350m in military assistance to Ukraine as European nations announced plans to send more weapons.

The Ukrainian capitol of Kyiv saw sporadic fighting and missile strikes as Russian forces attacked the city overnight on Friday. In a video message, president Volodymyr Zelensky vowed to resist the Russian attack and refused a US offer to flee the country.

"We will fight for as long as needed to liberate our country," he said.

Mr Trump praised Mr Zelensky in his speech, calling him a “brave man.”

“I like him because during that ridiculous impeachment time [...] the president of Ukraine said ‘he did nothing wrong,’” he said, referring to a phone call between the two leaders that led to Mr Trump’s impeachment.

The former president also made parallels between the Russian invasion of Ukraine and migrants attempting to cross the Mexico-US border.

“You can’t defend Western civilisation if you would not be able to defend your own civilisation,” he said.

“I believe Americans deserve a president who will stop the invasion of our country also.”