President Donald Trump reportedly berated the Australian prime minister during a phone call Saturday that ended abruptly less than halfway through its scheduled duration. Trump was said to be angry about a deal put in place by former President Obama that guaranteed the U.S. would take 1,250 refugees from an Australian detention center — a promise the new president called “the worst deal ever.”

The call between Malcolm Turnbull and Trump came on the same day as the new U.S. president held phone calls with four other world leaders — German Chancellor Angela Merkel, Japanese Prime Minister Shinzo Abe, French President François Hollande, and Russian President Vladimir Putin. Given the deep ties between Australia and the U.S. in the past, the call with Turnbull was expected to be the most straightforward. Instead Trump described it as “the worst call by far” — according to senior White House officials speaking to the Washington Post.

The call was scheduled to last for an hour, but Trump ended it after just 25 minutes. Late on Wednesday, Trump reasserted his strong opposition to the refugee program, calling it a “dumb deal” on Twitter, and promising to investigate it:

The U.S. has pledged to take 1,250 refugees from Australian detention centres located on the island of Nauru and Papua New Guinea. Many of the refugees held there come from Somalia, Iran, Iraq and Sudan – among the seven countries whose citizens Trump’s executive order bans from entering the U.S for the next 90 days.

According to the Washington Post sources, Trump told Turnbull that if he agreed to take the refugees, he “was going to be killed” politically and went on to suggest that Australia was trying to export the “next Boston bombers.”

When asked about the call, Turnbull refused to give any detail about what was said. “These conversations are conducted candidly, frankly, privately,” Turnbull said on Thursday. “If you see reports of them, I’m not going to add to them.”

However, government sources speaking to Sky News in Australia confirmed that the call was cut short mid-conversation, with Trump being said to have “yelled” at Turnbull. The prime minister reportedly later told his aides: “Trump is a bully.”

Australia and the U.S. have had diplomatic ties for 76 years and have strong bilateral defense and security cooperation, with U.S. troops fighting alongside Australian troops for decades. Just last year Obama and Turnbull reaffirmed their countries’ close relationship on matters involving terrorism, combating cyberattacks, and trade.

The day before the call with Turnbull, Trump reportedly angered another world leader. According to a leaked transcript of a call to Mexican President Enrique Peña Nieto, seen by AP, he threatened to send U.S. troops into the country: “You have a bunch of bad hombres down there. You aren’t doing enough to stop them. I think your military is scared. Our military isn’t, so I just might send them down to take care of it.”