President Donald Trump told Philippine President Rodrigo Duterte, during an April 29 phone call, that two U.S. submarines were in waters off the Korean Peninsula, according to a transcript of the phone call obtained by the news site The Intercept.

The two presidents were discussing the threat posed by North Korea before Trump told Duterte, "We have a lot of firepower over there. We have two submarines — the best in the world — we have two nuclear submarines — not that we want to use them at all. I've never seen anything like they are but we don't have to use this but he could be crazy so we will see what happens," according to the transcript.

The transcript is an official Philippine Department of Foreign Affairs document, and its authenticity was corroborated by multiple government sources contacted by the Philippine news outlet Rappler, according to The Intercept.

The White House's readout of the phone call does not include the submarine comment and describes the conversation as "very friendly ... in which the two leaders discussed the concerns of the Association of Southeast Asian Nations (ASEAN) regarding regional security, including the threat posed by North Korea."

Howard Stoffer, an associate professor of national security at the University of New Haven and a former U.S. foreign service officer, said he would put Trump's sharing of the submarine information in the same category as his sharing details of an Islamic State terror threat with Russian Foreign Minister Sergey Lavrov and Russian ambassador to the U.S. Sergey Kislyak.

"I had clearances for 25 years, and in every occasion that I talked to the press, I was able to satisfy them with the information that they wanted and at the same time not go across the bridge," Stoffer said. "I don't think he knows how to do that. That's an art that he hasn't developed. He better develop it soon."

Asked whether there would be a reason for the Philippines to know the number of U.S. submarines in the region, Stoffer replied, "Absolutely not."

As president, Trump legally can share classified information with whomever he wants. "It's not a matter of legality," Stoffer said, noting that other countries such as Russia, China and Japan, know about the location of the two U.S. submarines.

The Navy usually does not publicly discuss submarine movements so as not to undermine a submarine's most significant advantage: its stealth.

"Every briefing the Navy provides to civilian leadership in Washington on the movements of our submarine force is done at the highest level of secrecy to protect its unique attribute of stealth," U.S. Joe Courtney, D-2nd District, said in a prepared statement.

In late April, the Navy announced that the USS Michigan, a guided-missile submarine, had arrived in the port city of Busan, South Korea, "for a routine visit during a regularly scheduled deployment to the Western Pacific." The announcement came days before Trump's phone call with Duterte.

j.bergman@theday.com