House Democrats have moved aggressively to draw up formal articles of impeachment against President Donald Trump, saying if action isn't taken swiftly, he's likely to corrupt the system again before next year's election.
Congress must act, US House Speaker Nancy Pelosi said. "The democracy is what is at stake."
"The president's actions have seriously violated the Constitution," she said in a sombre address at the Capitol. "He is trying to corrupt, once again, the election for his own benefit. The president has engaged in abuse of power, undermining our national security and jeopardising the integrity of our elections."
"Sadly, but with confidence and humility, with allegiance to our founders and a heart full of love for America, today I am asking our chairmen to proceed with articles of impeachment," Pelosi said.
Trump has insisted he did nothing wrong. He tweeted that the Democrats "have gone crazy."
At the core of the impeachment probe is a July phone call with the president of Ukraine, in which Trump pressed the leader to investigate Democrats, including political rival Joe Biden. At the same time the White House was withholding military aid from Ukraine, an ally bordering an aggressive Russia.
Seemingly eager to fight, Trump tweeted that if Democrats "are going to impeach me, do it now, fast." He has said he now wants to move on to a "fair trial" in the Senate.
Approval of articles of impeachment is considered likely in the Democratic-majority House. Conviction in a following trial in the Republican-dominated Senate seems very unlikely.
Once reluctant to pursue impeachment, warning it was too divisive for the country and needed to be bipartisan, Pelosi is now leading Congress into politically uncertain terrain for all sides just ahead of the election year.
She spoke solemnly and calmly, but that changed when she was asked as she was leaving if she hates Trump.
Pelosi stiffened, returned to the podium and responded sharply that the president's views and politics are for the voters to judge at elections but impeachment "is about the Constitution." She said that as a Catholic, she does not hate the president but rather is praying for him daily.
Trump quickly tweeted back that he didn't believe her.
Trump's allies argue that voters, not lawmakers, should decide the president's future. But Democrats say the nation cannot wait for the 2020 election, alleging Trump's past efforts to have foreign countries intervene in the presidential campaign are forcing them to act to prevent him from doing it again.
The Republican Leader of the House, Kevin McCarthy, said Pelosi is more concerned about tearing the president down than building the country up.
At the White House, press secretary Stephanie Grisham tweeted that Pelosi and the Democrats "should be ashamed."
House members are preparing to vote on the articles of impeachment in the Judiciary Committee, possibly as soon as next week.
The House is expecting a full vote by Christmas. The would send the issue to the Senate for a trial in the new year.
Australian Associated Press