President Donald Trump again took aim at former FBI director James Comey on Sunday morning, suggesting in a tweet that Comey might have secretly released even more information to the public than he has already admitted to doing.

"I believe the James Comey leaks will be far more prevalent than anyone ever thought possible. Totally illegal? Very 'cowardly!'" Trump said in a tweet sent from his personal account, @realDonaldTrump.

In sworn testimony before Congress on Thursday, Comey said that he instructed a friend to give a reporter details about what he remembers the president said in private conversations about the FBI's investigation of former national security adviser Michael Flynn.

The details came from meticulous notes that Comey compiled after each of the encounters, and Comey said he did not pass along any classified information.