WASHINGTON, Dec 24 (Reuters) - Democrats in the U.S. House of Representatives on Thursday aim to win quick passage of legislation providing $2,000 in direct payments to Americans as part of a coronavirus economic relief initiative after President Donald Trump unexpectedly insisted on the provision. The stakes in this long-shot bid are enormous, as millions of Americans desperately await some sort of new assistance from Washington in a COVID-19 pandemic that is spiraling out of control in the United States and other nations. Late on Monday, Congress overwhelmingly approved an $892 billion emergency coronavirus aid bill that contains a one-time, $600 payment to individuals to help them cope with a U.S. economy hobbled by the pandemic. The aid was attached to $1.4 trillion in funding to keep the federal government operating through this fiscal year, which ends on Sept. 30, 2021. But defying expectations, Trump on Tuesday hinted he might veto the gigantic legislation if the direct payments were not increased to $2,000 per person and if a slew of unrelated government spending projects, including foreign aid, were not jettisoned. Trump, who was awaiting receipt of the $2.3 trillion bill from Congress, did not explicitly say he would veto the bill in its current form. But with his warning, he put the coronavirus aid in limbo as well as the ability of the federal government to operate normally beyond next Monday, when existing money runs out. In a challenge to congressional Republicans who labored to keep the cost of the coronavirus aid bill below $1 trillion, Democrats joyfully embraced Trump’s demand for bigger stimulus checks for Americans. On Wednesday, House Speaker Nancy Pelosi tweeted: “Mr. President, sign the bill to keep government open! Urge McConnell and McCarthy to agree with the Democratic unanimous consent request for $2,000 direct payments! This can be done by noon on Christmas Eve!” Senate Majority Leader Mitch McConnell and House Minority Leader Kevin McCarthy, the top two Republicans in Congress, and their aides have been silent on Trump’s demand for bigger checks. But McCarthy, in a letter late on Wednesday to his fellow Republicans, described a counter-move his party planned to make on Thursday that would seek changes to the foreign aid component of the spending bill. Each side might end up blocking the other’s proposal in a stand-off that would leave the bill that passed on Monday unchanged. Employing a procedural maneuver rarely used for major legislation, Democrats early on Thursday were expected to try to ram the $2,000 payment initiative through the House in lightning speed with a unanimous vote. But to prevail, all House members of the 435-seat chamber would have to go along by not objecting to the maneuver. If the Democrats’ gambit fails, it would be up to Trump to either sign the combined $2.3 trillion in coronavirus aid and government funding into law, or veto it. Congressional backers might have the votes to override a veto. If not, Congress and the White House would be in a potentially chaotic showdown just weeks before Trump is replaced by President-elect Joe Biden, a Democrat, on Jan. 20. In order to avoid a government shutdown, Congress could keep operations running by passing a fourth stopgap funding bill before midnight Monday. For that option to work, lawmakers would need Trump’s cooperation at a time when he is still consumed by his loss to Biden in the Nov. 3 presidential election. The stopgap bill would not include coronavirus aid, however. In another showdown with Trump, Congress wants to override his veto on Wednesday of a bill authorizing U.S. military programs. The House aims to vote on Monday and the Senate could follow up as early as Tuesday.