Former Vice President Joe Biden's campaign accused President Trump of "coddling" dictators in his meetings with North Korea's Kim Jong Un, Russian President Vladimir Putin and Turkish President Recep Tayyip Erdogan while overseas.

"President Trump's coddling of dictators at the expense of American national security and interests is one of the most dangerous ways he's diminishing us on the world stage and subverting our values as a nation," Biden campaign spokesman Andrew Bates said in a statement to CBS News.

The president held a last-minute meeting with Kim in the Demilitarized Zone separating North and South Korea on Sunday, becoming the first sitting president to set foot on North Korean soil. His meeting with Kim came after the G20 summit in Japan, where he met with Putin and Erdogan.

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As the president was flying back from his overseas trip, the Biden campaign said Mr. Trump "yet again fawned over Kim Jong-un — to whom he's made numerous concessions for negligible gain."

The campaign said the president "joked with Vladimir Putin about our election security and 'getting rid' of journalists, and even expressed sympathy for Turkey buying Russian missiles."

The statement came before Mr. Trump touched down on U.S. soil, a departure from the campaign's previous approach to criticizing the president while he is overseas. On his last trip to Asia in May, Mr. Trump indicated his agreement with Kim that Biden has a "low IQ." The Biden campaign waited until Mr. Trump returned from that trip to call his comments "beneath the dignity of the office."

The latest exchange between Biden and the president also comes after the first Democratic primary debate, where foreign policy mostly took a backseat to domestic issues. On the campaign trail, Biden regularly emphasizes the need to strengthen relationships with U.S. allies, which Biden argues have been severely strained by the current administration.

"His conduct reinforces that we urgently need a president who can restore our standing in the world, heal relationships with key allies Trump has alienated, and deliver real change for the American people," the campaign statement on Sunday added.

Caitlin Conant contributed to this report.