WASHINGTON (REUTERS) - US President Donald Trump will meet on Monday (May 21) with Justice Department and intelligence officials to discuss his order to look into whether his 2016 presidential campaign was infiltrated or surveilled under the Obama administration, a White House official told Reuters.

Trump will meet at 3pm (3am Singapore time) with Deputy Attorney General Rod Rosenstein, FBI Director Christopher Wray and Director of National Intelligence Dan Coats, the official said.

Trump on Friday (May 18) suggested that the FBI may have planted or recruited an informant in his campaign, citing unidentified reports that at least one FBI representative was "implanted"there.

On Sunday (May 20), he asked the Justice Department to look into the allegations.

Hours later, a spokeswoman said the department said it had asked the Inspector General to expand a review of the process for requesting surveillance warrants to include determining whether there was impropriety or political motivation in how the FBI conducted its investigation.

"If anyone did infiltrate or surveil participants in a presidential campaign for inappropriate purposes, we need to know about it and take appropriate action," Rosenstein said in a statement on Sunday evening.

Federal investigators are looking into whether Russia tried to sway the election and if it worked with the Trump campaign to do so.

Trump has denied any collusion and repeatedly dismissed the investigation as a "witch hunt."