The Pentagon warned against using Signal in a memo just last week, according to NPR. It cited threats from Russian hackers.

As Washington was roiled by the news that one of President Donald Trump’s top aides added a journalist to a group chat discussing military plans, many Republicans going to the polls to replace that White House aide’s old U.

The revelation that President Donald Trump's most senior national security officials posted the specifics of a military attack to a chat group that included a journalist hours before the attack took place has raised many questions.

A messaging app called Signal was recently the preferred communications platform for top officials in the Trump administration to discuss war plans.

Senior government officials mistakenly invited the editor in chief of the Atlantic to a group chat on the messaging app Signal, where the focus of conversation was U.S. airstrikes against rebel groups in Yemen.