WASHINGTON - Donald Trump faced calls from his own party to show more restraint on Twitter amid a storm of outrage Sunday over the president revealing the name of a man widely thought to be the whistleblower who triggered his impeachment.

Criticism has been growing since Trump retweeted an attack that included the name of the reported CIA staffer at the heart of the Ukraine scandal -- an act that could violate the whistleblower's guaranteed anonymity under the law.

"If the president would tweet a little bit less, it wouldn't cause brain damage. But the president does not have to take my advice, nor do I expect him to," Republican Senator John Kennedy, a key Trump ally, told "Fox News Sunday."

Trump is ending 2019 as the third president in US history to be impeached after pressuring Ukraine to investigate Joe Biden, a rival in his 2020 reelection bid.

The historic rebuke by the Democratic-controlled House of Representatives for abuse of office and obstruction of Congress is unlikely to pass the Republican-controlled Senate in a trial expected to begin in January.

But Trump, who is reportedly eager to celebrate his acquittal, has appeared increasingly frustrated that no date has been set for the trial amid a partisan standoff over its rules.

The president spent much of Friday amplifying pro-Trump and anti-Democrat tweets from suspicious-looking Twitter accounts at the start of what would become a weekend-long rant against the impeachment process.

The incendiary whistleblower retweet was no longer visible in the president's timeline by Saturday morning, although it was not clear who had removed it.

Political action group The Democratic Coalition tweeted Sunday that "while Trump has repeatedly backed efforts to unmask the whistleblower, his retweet marks the first time he has directly sent the alleged name to his 68 million followers." -AFP