President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE referred to Montenegro's prime minister as a "whiny punk bitch" after video of Trump appearing to shove the foreign leader went viral following last year's NATO summit, former White House aide Omarosa Manigault Newman Omarosa Onee Manigault NewmanTrump hurls insults at Harris, Ocasio-Cortez and other women Pelosi makes fans as Democrat who gets under Trump's skin The Memo: Impeachment's scars cut deep with Trump, say those who know him MORE claims in her new book.

In excerpts from “Unhinged: An Insider's Account of the Trump White House" obtained by the New York Daily News, Manigault Newman questions her former boss over video that appears to show Trump grabbing the arm of Prime Minister Duško Marković as he moves toward the front of a group of leaders.

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“I asked him, ‘You came off a little aggressive. Why did you do that?’ ” Manigault Newman writes.

“Oh, he’s just a whiny punk bitch," Trump responded, according to Manigault Newman.

Video of the incident went viral last year, with social media users questioning whether the U.S. president had shoved his way to the front of the group of leaders.

Trump also faced criticism earlier this year when he referred to Montenegro as "a tiny country with very strong people" who might start World War III.

"Montenegro is a tiny country with very strong people. ... They are very aggressive people, they may get aggressive, and congratulations, you are in World War III," Trump said last month while appearing to question the purpose of NATO's Article 5, which states that an attack on one member is an attack on all.

The country's former president, Ranko Krivokapić, fired back, telling reporters that Trump was the "strangest president in the history of the United States."

"With this kind of president, with his knowledge of foreign policy, who knows what is going on?” he added. “Foreign policy is not his big thing."

Trump weathered similar criticism at home over the incident, with GOP Sen. John McCain John Sidney McCainAnalysis: Biden victory, Democratic sweep would bring biggest boost to economy The Memo: Trump's strengths complicate election picture Mark Kelly: Arizona Senate race winner should be sworn in 'promptly' MORE (Ariz.) accusing Trump of playing in to Russian President Vladimir Putin's hands.

Trump has faced criticism for his tense relationships with leaders of foreign countries considered to be U.S. allies, including Canada's prime minister, whom Trump personally called out on Twitter after a NATO summit in June.

The president referred to Justin Trudeau on Twitter as "meek and mild" earlier this year after disagreeing with Trudeau on trade issues at the summit, blaming Canada for a deficit with the U.S.