Donald Trump said he did not know if war plans accidentally leaked to a journalist should have been classified.

Asked if he still believed nothing classified was shared in a Signal group chat where top US officials discussed plans to bomb Houthi rebels in Yemen, Mr Trump shrugged his shoulders and replied that he was not sure.

“Well, that’s what I’ve heard,” the president said in the Oval Office on Wednesday after announcing new tariffs on a slew of products.

“I don’t know. I’m not sure. You have to ask the various people involved. I really don’t know.”

His response has shifted slightly since Tuesday when he said: “There was no classified information as I understand it.”

The messages in the Signal chat contained precise details about timings of the strikes, as well as the aircraft used and some information about targets.

The name of an undercover CIA agent was also mentioned in the chat, according to Jeffrey Goldberg, the editor in chief of The Atlantic, but the name has not been published.

The White House has repeatedly claimed the information shared on the messaging app was not classified as it sought to downplay the severity of the leak.

Mike Waltz, the national security advisor, said earlier this week that he was “embarrassed” by the incident and took “full responsibility”.

Marco Rubio, the secretary of state, on Wednesday said someone had made a “big mistake”.