President Donald Trump said on April 6 that the journalist who first reported a second missing airman in Iran could face jail if they refuse to disclose the source, citing national security risks.

“We’re looking very hard to find that leaker,” Trump said at a White House press conference. “They basically said that ‘we have one and there’s somebody missing.’ Well, they didn’t know there was somebody missing until this leaker gave the information.”

“So whoever it was, we think we’ll be able to find it out because we’re going to go to the media company that released it, and we’re going to say, ‘National security, give it up or go to jail.’ And you know who we’re talking about,” he said.

The president did not name the media outlet or the journalist he was referring to.

Trump said the leak had put Tehran on notice because “all of a sudden, the entire country of Iran knew that there was a pilot that was somewhere on their land that was fighting for his life.” He noted that Iran even offered a reward for anyone who could capture the airman.

“It became a much more difficult operation because a leaker leaked that we have one, we’ve rescued one, but there’s another one that we’re trying to get,” he said.

“They put this mission at great risk. They put that man at great risk, and they put the hundreds of people that went in looking for him [at risk], because everyone now knows that we’re going in.”

Seth Stern, chief of advocacy for Freedom of the Press Foundation, said in a statement in response to Trump’s remarks that journalists have the right to publish government leaks under the First Amendment.

“It does not disappear whenever the words ‘national security’ are uttered. To the extent that the government is allowed to withhold information, it’s up to the government to keep its secrets, not journalists,” Stern said.

Trump said the other airman had been successfully recovered at an earlier point, “which we did not confirm, because we did not want to jeopardize our second rescue operation.”

“This is the first time in military memory that two U.S. Pilots have been rescued, separately, deep in Enemy Territory. We will never leave an American warfighter behind,” he wrote in capital letters.