immigration@ (Adds Trump comments, Schumer on immigration, start of meeting at White House)
WASHINGTON, Sept 6 (Reuters) - Republican and Democratic congressional leaders on Wednesday clashed over raising the U.S. debt limit and the fate of 800,000 young adults brought into the United States illegally as children, as President Donald Trump pressed them to act.
Trump met at the White House with congressional leaders from both parties, with lawmakers facing several pressing legislative priorities.
Those include disaster relief for victims of Hurricane Harvey, raising the U.S. debt ceiling by early October to prevent an unprecedented default on U.S. government debt, and passing legislation for federal spending in the fiscal year that begins on Oct. 1 to avoid a government shutdown.
"We have many, many things that are on the plate," Trump told reporters at the beginning of a White House meeting with the congressional leaders heading into what promises to be frantic weeks of legislative work.
"Hopefully we can solve them in a rational way. And maybe we won't be able to. We'll probably know pretty much at the end of this meeting or the meetings that we'll be having over a short period of time," Trump added.
Trump on Tuesday gave a Congress controlled by his fellow Republicans six months to pass legislation to decide the fate of the 800,000 so-called Dreamers after rescinding a five-year-old program that had protected them from deportation.
Republican House of Representatives Speaker Paul Ryan said any legislation to address the Dreamers would also need to address border security, a position sure to antagonize Democrats.
"It's only reasonable and fitting that we also address the root cause of the problem, which is borders that are not sufficiently controlled, while we address this very real and very human problem that's right in front of us," Ryan told reporters.
Ryan also said any immigration legislation the House would consider would have to have the support of Trump.
Senate Democratic leader Chuck Schumer called on the Republicans to put forward legislation protecting the Dreamers without other issues attached.
"We could solve this problem tomorrow, rather than letting the fear of deportation hang over the heads of 800,000 Dreamers who are studying, working and some in the military, serving in the United States today," Schumer said on the Senate floor.
Even though Republicans control the White House and both chambers of Congress, they have been unable to pass any major legislation since Trump took office in January, most notably failing to approve a promised dismantling of the Obamacare healthcare law.
The House is expected to pass legislation on Wednesday providing the first installment of disaster aid in the aftermath of Hurricane Harvey. The measure includes $7.4 billion in added funds for the Federal Emergency Management Agency (FEMA) to help storm victims and $450 million for the Small Business Administration to help firms hurt by the hurricane.
The Senate is expected also to pass the measure this week, but could attach an unrelated measure raising U.S. borrowing authority, which would require House approval later in the week.
Trump also wants Congress to make good on his campaign promise for sweeping tax cuts and a major infrastructure spending bill. Trump last month had threatened to shut down the government if Congress does not provide funding for his planned wall along the U.S.-Mexican border.
On Tuesday, Trump wrote on Twitter that he wanted to work with both Democrats and Republicans on an immigration package.
The problems ahead were illustrated by the sniping from congressional leaders of the two parties before the meeting. Ryan called a Democratic plan for just a three-month increase in the nation's debt limit "ridiculous" and "disgraceful."
And Schumer called Trump's decision to terminate the Deferred Action for Childhood Arrivals (DACA) program created in 2012 by Democratic former President Barack Obama "heartless and brainless," a day after Pelosi called Trump's action a "shameful act of political cowardice."
At the beginning of the White House meeting, Trump put aside his own previous harsh words for the two Democratic leaders and thanked them for being there.
Republican Senate Majority Leader Mitch McConnell said it was critical for Congress to pass disaster relief legislation, prevent a U.S. debt default and keep the federal government open so that help could get to the victims of Hurricanes Harvey and Irma, which was headed toward Florida.
Trump has strained ties with lawmakers in his own party after he scolded many of them, including McConnell.
After McConnell last month said Trump had "excessive expectations about how quickly things happen in the democratic process," Trump discussed the possibility of McConnell leaving his post if he failed to make good on legislative goals such as healthcare, tax cuts and infrastructure legislation. "Mitch, get to work," Trump said on Aug. 10.
Trump also has lashed out at individual Republican lawmakers including Senators Bob Corker, Jeff Flake, John McCain and Lindsey Graham. Corker, the influential Senate Foreign Relations Committee Chairman, on Aug. 17 said Trump had not shown the stability or competence needed to succeed. (Additional reporting by Doina Chiacu, Richard Cowan, Jeff Mason and David Morgan; Writing by Will Dunham; Editing by Alistair Bell)