WISCONSIN (CBS 58) -- Wisconsin Senator Ron Johnson is expressing concern about reports that Trump administration officials discussed sensitive military operations over a message app.

Those reports say high-level administration officials talked about plans for an attack in Yemen on Signal.

That's an app that's encrypted, but not government approved.

The editor in chief of The Atlantic says he was accidentally invited to join the group chat. Now, members of Congress are calling for an investigation.

"I think this is one more example of the kind of sloppy, careless, incompetent behavior, particularly toward classified information," said Sen. John Warner (D-Virginia). 

"We need to update how we handle things based on technology," said Sen. Ron Johnson. "I think that's obvious; this has happened administration after administration. I try and tell all the nominees to jealously-or just, faithfully, follow the Federal Records Act."

The White House press secretary said Tuesday morning that "no war plans" were discussed, and no classified material was sent to the thread.