US Defence Secretary Pete Hegseth shared details of a March attack on Yemen's Iran-aligned Houthis in a message group that included his wife, brother and personal lawyer, the New York Times reported on Sunday, raising more questions about his use of an unclassified messaging system to share highly-sensitive security details.

Hegseth allegedly shared the same details of the attack that were revealed last month by The Atlantic magazine after its editor-in-chief, Jeffrey Goldberg, was included in a separate chat on the Signal app by mistake, in an embarrassing incident involving all of US President Donald Trump's most senior national security officials.

The Times, citing four sources familiar with the message group, said that second chat included details of the schedule of the air strikes.

Hegseth's wife Jennifer, a former Fox News producer, has also reportedly attended sensitive meetings with foreign military counterparts, the Wall Street Journal has separately reported.

Revelations of another use of Signal for classified information come as one of Hegseth's leading advisers, Dan Caldwell, was escorted from the Pentagon last week after being identified during an investigation into leaks at the Department of Defence, a US official told Reuters.

Following Caldwell's departure, less senior officials Darin Selnick, who recently became Hegseth's deputy chief of staff, and Colin Carroll, who was chief of staff to Deputy Defence Secretary Steve Feinberg, were put on administrative leave, officials said.

The Trump administration has aggressively pursued leaks, an effort that has been enthusiastically embraced by Hegseth at the Pentagon.

The Pentagon was not immediately available for comment. (Reuters)