A US House of Representatives panel is expected to approve impeachment charges against President Donald Trump later in a marathon session of rancorous debate.
The judiciary committee is debating two articles of impeachment alleging abuse of power and obstruction of Congress.
A full vote by the Democratic-run House next week will likely make him the third US president ever impeached.
But the Senate, controlled by Mr Trump's fellow Republicans, is not expected to remove him from office.
"No crime!" the US president said on Twitter early on Thursday.
What do the articles of impeachment say?
Mr Trump is accused of trying to force Ukraine to launch a corruption investigation into his political rival Joe Biden, a leading Democratic contender for the White House next year; and obstruction of Congress for stonewalling the House investigation.
The Democrats who run the committee have agreed the language of the nine pages detailing the charges, saying that Mr Trump "betrayed the nation" by acting "corruptly".
There are 41 members on the panel, which is expected to vote along party lines on Thursday afternoon local time.
Republicans are trying to introduce amendments, but unified Democrats on the panel are rebuffing such proposed changes
What is being said in the debate?
The judiciary committee launched the two-day session on Wednesday evening at the Capitol.
Republicans decried the impeachment case as "hot garbage", while one Democrat accused the president of a "constitutional crime spree".
Jim Jordan, an Ohio Republican, said Democrats were only impeaching Mr Trump because "they don't like the 63 million people who voted for this president, all of us in flyover country, all of us common folk".
But Democrats rebuked Republicans for their loyalty to Trump.
"Wake up!" said Representative David Cicilline, accusing the other party of "wilfully ignoring the facts to protect a corrupt and dangerous president".
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What will happen next week in the House?
A handful of Democrats in swing districts remain unsure how they will vote on impeachment when it comes to next week's debate.
But Democrats have a 36-seat lead over Republicans in the House so passage is still expected to go ahead.
Democrats stepped back from including in the impeachment charges findings by Special Counsel Robert Mueller that Mr Trump may have obstructed the justice department's inquiry into alleged Russian election meddling.
The party's lawmakers from more conservative districts have argued the focus should be limited to Ukraine.
Democratic leader Nancy Pelosi said on Thursday they would not whip the historic vote, allowing members to make their own personal choice.
What will happen in the Senate?
The Senate is expected to hold a trial next month on the charges and acquit the president.
Republicans who hold sway in the chamber appear to favour a quick vote, limiting political fanfare.
Mr Trump has indicated he would like to see witnesses called such as Joe Biden and his son, Hunter, who worked for a Ukrainian gas firm that the US president wanted investigated.
Mitch McConnell, the Senate majority leader, said on Wednesday no decision had yet been made over how to conduct the trial.
Analysts say the 100-seat chamber does not have the 67 votes needed to remove Mr Trump from office.
