ISTANBUL

US Defense Secretary Pete Hegseth ordered the installation of the Signal messaging app on a desktop in his Pentagon office, demonstrating how he integrated the unclassified commercial app, central to his political issues, with secure systems used to protect sensitive military information, the Washington Post reported Wednesday.

Hegseth essentially "cloned" the Signal app from his mobile phone, according to sources familiar with the matter.

Hegseth’s decision earlier this year to install Signal on a desktop computer in the Pentagon was a workaround that enabled him to use Signal in a classified space, where his cellphone and other personal electronics are not permitted, and communicate with ease with anyone, other government officials or his family, who is outside of the imposing military headquarters.

Other aides, including Joe Kasper, Hegseth’s chief of staff at the time, voiced an interest in using Signal on Pentagon computers, but it is unclear how widely the app’s use proliferated, said those familiar with the matter. It is also unclear whether Hegseth and his team of political advisers have adhered to US law that would require them to preserve messages on the app.

Sean Parnell, Hegseth’s spokesman, said Hegseth "has never used and does not currently use Signal on his government computer." However, two sources said he had Signal installed on a second office computer and showed interest in installing a program for sending conventional text messages.

Hegseth's use of Signal has raised concerns after it was revealed last month that he shared sensitive details about a military operation in Yemen. He used a group chat app by White House National Security Adviser Michael Waltz and a smaller one he created for his family and aides.

While the Biden administration approved limited use of Signal in 2023, sharing classified material on the app is prohibited.

"Signalgate" erupted after the Atlantic magazine reported that Waltz mistakenly included its top editor in a Signal group discussing a US operation against Iran-backed militants in Yemen. The group, which included nearly 20 senior officials, discussed details of the operation, including timing, aircraft and weapons, which former defense officials said would likely have been classified.

After the incident, senators Roger Wicker and Jack Reed requested a review of Hegseth's use of Signal by the Pentagon’s inspector general, who agreed to investigate.

The New York Times later reported that Hegseth also shared details about the Yemen operation in a separate Signal group with his wife, Jennifer; his brother, Phil; and his lawyer, Tim Parlatore. Jennifer has no role at the Pentagon; Phil works at the Pentagon and Parlatore recently rejoined the Navy to focus on military justice.

Hegseth fired three senior aides last week and accused them of leaking sensitive information, but they denied the claims, calling them slanderous.

Adm. William McRaven stated, “Clearly, the information broadcast on Signal was classified” and advised Hegseth to take responsibility and rely on trusted military officials.

"You have to have a little swagger and you have to have a little confidence, but once again, you better have a little humility going into a job like this," said McRaven. Hegseth confirmed Kasper's departure, but the Pentagon has not named a new chief of staff.