WASHINGTON – Sen. Kamala Harris on Tuesday repeated her call for Twitter to suspend President Donald Trump's account, sending a formal letter to the company's CEO Jack Dorsey that said Trump's attacks on the whistleblower who helped sparked an impeachment inquiry violate the site's rules.

"I write to call your attention to activity that President Trump has been engaged in on his Twitter account, which appears to violate the terms of the user agreement that your company requires all users on the platform adhere to," she said at the opening of her letter.

Harris pointed to tweets Trump posted in the past week that "target, harass, and attempt to out the whistleblower who set forth credible allegations that the President has abused his power by urging a foreign government to investigate a domestic political rival."

The whistleblower's complaint alleges Trump pressured the Ukrainian government to investigate former Vice President Joe Biden and his son, Hunter Biden, in what many Democrats say was an abuse of power.

"Look let's be honest, @realDonaldTrump's Twitter account should be suspended," reads the pinned tweet on the California Democrat's account page.

"Hey @Jack. Time to do something about this," Harris tweeted at Dorsey on Tuesday after Trump tweeted that the impeachment inquiry against him is a "coup" attempt designed to "take away" Americans' "God-given rights."

More:Donald Trump sets Twitter record as White House fights off impeachment inquiry

In the letter, Harris cited tweets in which Trump said a "leaker or spy" or "partisan operative" was behind the complaint and when he said the whistleblower's identity should be revealed to him. She said it was important to put the tweets in context because Trump had implied the whistleblower was a "'spy' who may have committed treason, and further implied that the punishment should be death."

In addition. she said Trump had used tweets to intimidate the person who may have given the whistleblower information and to accuse House Intelligence Committee Chairman Adam Schiff of treason.

'Horrific and chilling':Whistleblower advocates complain as Trump tries to identify source of Ukraine complaint

Harris also pointed to a tweet in which Trump quoted a pastor who said his removal from office could lead to civil war.

"These are blatant threats. We need a civil society, not a civil war," Harris said. "These tweets represent a clear intent to baselessly discredit the whistleblower and officials in our government who are following the proper channels to report allegations of presidential impropriety, all while making blatant threats that put people at risk and our democracy in danger."

She said Twitter had suspended other users for similar violations, including InfoWars host Alex Jones and conservative actor James Woods.

"Others have had their accounts suspended for less offensive behavior. And when this kind of abuse is being spewed from the most powerful office in the United States, the stakes are too high to do nothing," she wrote.

"No user, regardless of their job, wealth, or stature should be exempt from abiding by Twitter’s user agreement, not even the President of the United States."

Harris is far from the first person to argue that Trump's Twitter account should be suspended for violating the platform's rules against harassment, abuse, violence and hateful conduct. But the company has been reluctant to take such action, explaining in a January 2018 post that, "Blocking a world leader from Twitter or removing their controversial Tweets would hide important information people should be able to see and debate."

Several high-profile accounts have been suspended for violating the site's rules in recent years. Conservatives have alleged that the site has disproportionately targeted them for such violations, accusing Twitter and other social media companies like Facebook of political bias.

During an interview with CNN on Monday, host Anderson Cooper told Harris that suspending Trump's Twitter account would likely prompt him to tell his supporters that he was the victim of rich Silicon Valley Democrats who wanted to silence him.

"I'm sure that will be said, but we have to also agree that when the president of the United States speaks her words are very powerful and should be used in a way that is not about belittling, much less harming, anyone," Harris said. "And this president has I think never fully appreciated that responsibility.

"And if he's not going to exercise self-restraint, then perhaps there should be other mechanisms in place to make sure that his words do not, in fact, harm anyone," she added.

"I think there is plenty of evidence to suggest that he is irresponsible with his words in a way that could result in harm to other people. And so the privilege of using words in that way should probably be taken from him," she said.