WASHINGTON- Democrats in the U.S. House of Representatives were expected to unveil two formal charges against Donald Trump on Tuesday, moving quickly toward a momentous vote on whether to impeach the Republican president.

Democratic lawmakers planned to make an announcement on articles of impeachment on Tuesday morning, Foreign Affairs Committee Chairman Eliot Engel said as he left House Speaker Nancy Pelosi's office. He did not elaborate.

Pelosi's office said later that House committee leaders would hold a news conference on Tuesday morning to announce the next steps in the impeachment inquiry.

If the House approves the articles, as expected, the Republican-controlled Senate would hold a trial to decide whether to remove the president from office. A conviction is considered unlikely but could taint Trump as he seeks re-election in November.

A senior House Democratic aide told Reuters they were expected to draft two articles of impeachment against Trump, one on abuse of power and the other on obstruction of Congress. 

The Judiciary panel could vote this week on whether to send formal charges, known as articles of impeachment, to the full House.

Democrats accuse Trump of abusing the power of his office by withholding aid to Ukraine, a vulnerable U.S. ally facing Russian aggression, as well as dangling a possible White House meeting to get Ukrainian President Volodymyr Zelenskiy to launch a probe of a Democratic political rival in the 2020 presidential race.

After weeks of investigation and hearings in the Democratic-led House, committee leaders met with Pelosi following the last scheduled impeachment hearing on Monday evening.

Jamie Raskin, a Judiciary Committee Democrat, told reporters later that Democrats have identified two patterns of misconduct by Trump: "Bringing in foreign governments into our politics in order to corrupt our elections" and "working to cover up this kind of misconduct by blockading witnesses, withholding evidence and trying to stop people from testifying."

Trump has denied wrongdoing and calls the inquiry a hoax. The White House has refused to participate in the hearings in the House because it says the process is unfair.

He attacked the impeachment effort in a Twitter post early Tuesday, saying to impeach a president when the country has such a strong economy "and most importantly, who has done NOTHING wrong, is sheer Political Madness!"

Pelosi launched the impeachment inquiry on Sept. 24 after a whistleblower reported concerns over a July 25 telephone call in which Trump sought help from Zelenskiy to investigate former Vice President Joe Biden, a leading contender in the Democratic race to challenge Trump in next year's election.

Democrats say their investigation also shows Trump withheld $391 million in military aid and a White House meeting to get his Ukrainian counterpart to investigate Biden and his son Hunter Biden, as well as a debunked theory that Ukraine, not Russia, interfered in the 2016 U.S. election.

Republicans argue Trump did nothing improper in his call with Zelenskiy and say there is no direct evidence he withheld aid or a White House meeting in exchange for a favor.

Jerrold Nadler, the Democratic chairman of the House Judiciary Committee, closed the nine-hour hearing on Monday with a condemnation of Trump's actions.

"The facts are clear. The danger to our democracy is clear and our duty is clear," Nadler said. Trump "constitutes a continuing threat to the integrity of our elections and to our democratic system of government.

"Such conduct is clearly impeachable. This committee will proceed accordingly."

The final decision on articles of impeachment would be made by Pelosi, Nadler, House Intelligence Committee Chairman Adam Schiff and the leaders of three other committees that began investigating Trump's presidency this year, according to aides.

The Judiciary Committee would need to give 24 hours' notice before meeting to vote on whether to forward the articles to the full House for a final impeachment vote by the chamber.

Leadership was likely to share the plan with rank-and-file members of the House Democratic caucus, which is due to meet on Tuesday morning in the U.S. Capitol.

(Reporting by Susan Cornwell, Richard Cowan, David Morgan; Writing by Doina Chiacu; Editing by Peter Cooney, Lincoln Feast and Nick Zieminski) ((doina.chiacu@thomsonreuters.com; 202-898-8322;))