London - Joe Biden said in his first post-presidential interview that President Donald Trump's pressure on Ukraine to abandon Russian territory is equal to "modern app", a historical term that refers to efforts to stop Nazis from blocking the Nazi annexation of European land in the 1930s.

Biden told BBC Radio 4's "Today" plan in remarks aired on Wednesday that Trump's statements about the acquisition of Panama, Greenland and Canada have caused the United States to distrust Europe.

"What did the president say this?" Biden said. "That's not who we are. We're about freedom, democracy, opportunity, not about confiscation."

He also said leaving the U.S. presidential election four months from Election Day was a "hard decision" to allow former Vice President Kamala Harris to challenge Trump. However, he added that this move was earlier as some critics suggested “(not)important things.”

The term Appasement refers to the efforts of former British Prime Minister Neville Chamberlain to appease Adolf Hitler's annexation of European land in the 1930s, a migration that failed to stop World War II.

Trump has long viewed the war in Ukraine as a waste of life and American taxpayers’ money. Trump ordered the cessation of aid to Ukraine in his early years as president - and then resumed. Last week, the two countries signed an agreement to grant the U.S. access to Ukraine's huge mineral resources - a return on investment that could pave the way for more U.S. aid, Trump believes.

He also said that Crimea, a strategic peninsula in the Black Sea in southern Ukraine, was illegally annexed by Russia in 2014 and “will be with Russia.”

Biden says he fears erosion between the U.S. and Europe under Trump, NATO members reconsider whether they trust the U.S.

Biden told the BBC: "Europe will lose confidence in the certainty of the U.S. leadership." He added that mainland leaders asked, "'Can I rely on the U.S.? Will they be there?''

Biden said that particular concern was the government's proposal to allow Russia to retain some Ukrainian territory to implement a peace agreement that would end the fight.

"This is a modern app kiss," Biden said.

Biden said Trump's defeat of Ukrainian President Volodymyr Zelenskyy in the Oval Office in February was "under America."

"I don't understand how they don't understand the power of the league," Biden said of the Trump administration on Monday.

Asked about Trump's victory celebrations for his 100-day presidency, Biden replied that he would let history make a judgment.

"I can't see anything that wins," he said.