Defense Secretary Pete Hegseth and other members of the Trump administration are being investigated for their recent use of a Signal app before a military strike on the Houthis in Yemen.

Republican calls to investigate a group chat in which White House national security officials shared sensitive military information has intensified, with Oklahoma Senator James Lankford saying it is "entirely appropriate".

The inspector general review follows revelations that top Trump officials used the unclassified platform Signal to coordinate military strikes in Yemen.