U.S. President Donald Trump said on Monday that he stood behind Defense Secretary Pete Hegseth after reports emerged of Hegseth sharing details of a March attack on Yemen's Houthis in a messaging group that included his wife, brother, and personal lawyer.

The revelation that Hegseth used the unclassified messaging app Signal to share highly sensitive security information for the second time comes at a tense moment for him and the Pentagon. Senior officials were ousted last week as part of an internal leak investigation.

"Pete's doing a great job. Everybody's happy with him," Trump said. Asked if he remained confident in Hegseth, Trump said, "Oh totally."

"Ask the Houthis how he's doing," Trump said. 

The U.S. military, under Trump, has ramped up its bombing campaign against the Iran-backed Houthi group.

In the second chat, Hegseth reportedly shared details of the attack similar to those revealed last month by The Atlantic magazine, after its editor-in-chief, Jeffrey Goldberg, was mistakenly included in a separate Signal group, according to Reuters on Sunday. 

White House spokesperson Karoline Leavitt denied a report by National Public Radio that the Trump administration had begun searching for a new defense secretary.

The second Signal group, which included about a dozen people, was initially created during Hegseth's confirmation process to discuss administrative matters rather than detailed military planning. Among its members was Hegseth's brother, who serves as a Department of Homeland Security liaison to the Pentagon.

Hegseth's wife, Jennifer, a former Fox News producer, has reportedly attended sensitive meetings with foreign military counterparts, according to publicly released Pentagon images.

A person familiar with the matter told Reuters that Hegseth had previously been advised not to share information over unsecured systems like Signal, prior to his actions last month.

The Pentagon Inspector General's office announced earlier this month that it was opening a probe into Hegseth's use of the unclassified commercial texting application to coordinate on the highly sensitive March 15 launch of U.S. strikes on Houthis.