"There was no mention of any of this classified evidence during the All Senators Briefing last Wednesday. ... Furthermore, on Sunday Secretary Esper said President Trump 'didn't cite a specific piece of evidence' regarding an imminent attack on four embassies and that Secretary Esper 'didn’t see' that evidence," the senators wrote.

The nine senators are requesting a classified briefing by the end of the week.

"It is vital for the American public to know if intelligence is being manipulated or inaccurately represented by their government to justify an assassination of a foreign official," the senators added.