AMNA NAWAZ: Welcome to the "News Hour."

Today, "The Atlantic" magazine published the full messages among the president's national security aides right before the launch of military strikes in Yemen.

GEOFF BENNETT: The new messages written on the commercially available app, Signal, show that the secretary of defense posted the timing and weapons used in the attack 30 minutes before the operation began.

Those details have shocked many in the national security community and dominated a prescheduled House Intelligence Committee hearing on Capitol Hill today.

Nick Schifrin starts our coverage.

REP. RAJA KRISHNAMOORTHI (D-IL): This is classified information.

NICK SCHIFRIN: At a hearing dedicated to worldwide threats, Democrats today pointed their criticism inside the administration.

REP. CHRISSY HOULAHAN (D-PA): Communicating these sorts of things in Signal is not OK.

Targets, times,those kinds of things are absolutely classified.

NICK SCHIFRIN: The accusations followed "The Atlantic"'s publishing Secretary of Defense Pete Hegseth messages that he wrote before surprise attacks on Houthi leaders and targets, revealing extraordinary detail.

"Time now, 11:44 Eastern.

Weather is favorable.

Just confirm with Central Command we are a go for mission launch, 12:15 p.m., F-18s launch first strike package, 1:45 p.m., trigger-based F-18 first strike window starts.

Target terrorist is at his known location, 2:10 p.m., more F-18s launch, 2:15 p.m. strike drones on target, 3:36 p.m., F-18 second strike starts.

We are currently clean on operational security.

Godspeed to our warriors."

REP. JIM HIMES (D-CT): Everyone here knows that the Russians or the Chinese could have gotten all of that information.

And they could have passed it on to the Houthis, who easily could have repositioned weapons and altered their plans to knock down planes or sink ships.

I think that it's by the awesome grace of God that we are not mourning dead pilots right now.

NICK SCHIFRIN: Democrats pointed to a January 2025 Department of Defense manual that lists military plans, weapons systems or operations as the first reason to call information classified.

National Security Adviser Mike Waltz later added real-time intelligence that the U.S. targeted "the Houthis' top missile guy.

We had positive idea of him walking into his girlfriend's building, and it's now collapsed."

Those details' source is provided by sensitive classified collection.

And multiple former defense and intelligence officials told "PBS News Hour" today that they would consider this level of detail classified and exquisite that could have put troops at risk.

But Secretary of Defense Pete Hegseth, who holds declassification authority, called the accusations baseless.

PETE HEGSETH, U.S. Defense Secretary: Because they know it's not war plans.

There's no units, no locations, no routes, no flight paths, no sources, no methods, no classified information.

NICK SCHIFRIN: Director of National Intelligence Tulsi Gabbard also defined classified material narrowly.

TULSI GABBARD, U.S. Director of National Intelligence: The conversation was candid and sensitive.

But as the president and national security adviser stated, no classified information was shared.

There were no sources, methods, locations or war plans that were shared.

NICK SCHIFRIN: That point shared by Republicans with Gabbard and CIA Director John Ratcliffe.

REP. AUSTIN SCOTT (R-GA): Was the target terrorist named in the text or was it simply referred to as target terrorist?

TULSI GABBARD: The target was not named.

REP. AUSTIN SCOTT: Thank you.

Was the location named?

TULSI GABBARD: Congressman, no, no locations were named.

REP. FRENCH HILL (R-AR): Were there any war plans distributed in that Signal chat?

JOHN RATCLIFFE, CIA Director: No, Congressman.

REP. FRENCH HILL: And were sources and methods that would compromise our intelligence system or your agents in the field around the world, were they discussed on the Signal chat?

JOHN RATCLIFFE: No.

NICK SCHIFRIN: But, this afternoon, Senate Armed Services Chairman Republican Roger Wicker said he was asking the administration to open an inspector general investigation.

And he said -- quote -- "The information as published recently appears to me to be of such a sensitive nature that, based on my knowledge, I would have wanted it classified."

Regardless of the domestic political debate, the U.S.' closest intelligence allies are watching.

Canadian Prime Minister Mark Carney is one of the Five Eyes, intelligence-sharing alliance.

MARK CARNEY, Canadian Prime Minister: It's a serious, serious issue.

And all lessons must be taken.

NICK SCHIFRIN: As President Trump has said when it comes to his national security adviser and Signal -- quote -- "He probably won't be using it again."

For the "PBS News Hour," I'm Nick Schifrin.