Homeland Security Secretary John Kelly on Sunday condemned intelligence leaks after the Manchester attack as “darn close to treason.”

The sharing of intelligence related to the case between British counterterrorism police and U.S. officials was briefly paused after pictures from the scene of Monday's deadly Ariana Grande concert bombing were published in the New York Times – and authenticated to NBC News by a senior U.S. law enforcement official. The name of the suspected attacker was also released to the press.

“I believe when you leak the kind of information that seems to be routinely leaked - high, high level of classification… I think it’s darn close to treason,” Kelly told NBC’s “Meet The Press.”

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The New York Times did not reveal how it obtained the photos.

“I don’t know where the leak came from,” Kelly said. “But I will tell you this, as I always do in cases like this, I immediately called my counterpart in the UK. And after offering my condolences about the attack… She immediately brought this topic up. And, if it came from the United States, it’s totally unacceptable. And I don’t know why people do these kind of things, but it’s borderline, if not over the line, of treason.”

British Prime Minister Theresa May warned that she would speak with President Trump about the importance of tightly held information between the two countries.

In a statement Thursday, President Trump called leaks after the attack “deeply troubling” and asked the Department of Justice to try to find out where they originated.

Kelly on Sunday also said he didn’t take issue with a report, originally published in the Washington Post, that indicated White House Senior Adviser Jared Kushner, also President Trump's son-in-law, proposed a secret communication channel with the Kremlin so that discussions before the inauguration could not be detected.

NBC News reported on Thursday that Kushner is under scrutiny related to the Russia investigations, though not a subject of the investigations, like Michael Flynn or Paul Manafort.

“I know Jared, he’s a great guy, decent guy,” Kelly said. “His number one, number one interest, really, is the nation so you know there’s a lot of different ways to communicate, backchannel, publicly with other countries. I don’t see any big issue here relative to Jared.”

“It was before the government was in place during the transition period I think, from what I understand,” Kelly continued. “And I think any time you can open lines of communication with any one, whether they’re good friends or not so good friends, is a smart thing to do.”

Kelly defended Kushner from reports that Kushner wanted to set up these “backchannel” communications with Russia during a period when U.S. intelligence agencies declared that Russia had attempted to interfere with the last election.

“Just because you have a backchannel, if indeed that’s what Jared was after, doesn’t mean that he then keeps everything secret,” Kelly said. “I mean he shares that. But the backchannel as I understand it, and of course every administration has had it all the way forever. Backchannel communications with people are ways to communicate with people, again not in front of the press, as an example, but that information is not necessarily kept secret from the rest of the government.”