A recent phone conversation between U.S. President Donald Trump and controversial Philippines President Rodrigo Duterte has been leaked and published by the Intercept.

Of particular note is that Trump effusively praised Duterte for his prosecution of the Philippines' drug war, which has killed thousands and seen the alleged use of extrajudicial death squads.

It is what apparently prompted the call.

"I just wanted to congratulate you because I am hearing of the unbelievable job on the drug problem," Trump told Duterte. "Many countries have the problem, we have a problem, but what a great job you are doing and I just wanted to call and tell you that."

The official White House readout of the call, that occurred on Apr. 29., read: "They also discussed the fact that the Philippine government is fighting very hard to rid its country of drugs, a scourge that affects many countries throughout the world."

Trump also shared information with Duterte about the U.S. efforts against North Korea, telling Duterte that he has sent two nuclear submarines to the waters off the Korean peninsula. Trump has tried to rally other Asian nations, namely China, against Pyongyang in recent months.

Reuters noted that the disclosure to the Philippines leader is "likely to raise questions about his handling of sensitive information." Trump found himself in hot water earlier this month for a similar disclosure to Russia that the White House has defended.

Trump told Duterte leader Kim Jong Un is "a madman with nuclear weapons," and Duterte told Trump he fears the leader "might go crazy."

"What's your opinion of him, Rodrigo?" Trump at one point asked Duterte.

"He is not stable," Duterte said, assessing Kim as someone with "dangerous toys in his hands which could create so much agony and suffering for all mankind."