Top Democratic leaders abruptly pulled out of a planned meeting Tuesday with U.S. President Donald Trump after he attacked them on Twitter, casting doubt on the prospects for a quick agreement to avert a government shutdown at the end of next week.

Trump tweeted early Tuesday that "I don't see a deal!" with Senate minority leader Charles Schumer and top House Democrat Nancy Pelosi, and accused them of being soft on crime, taxes and illegal immigration.

Schumer and Pelosi shot back by cancelling the afternoon White House meeting and asking instead for immediate talks with top Republican leaders in Congress.

"Given that the president doesn't see a deal between Democrats and the White House, we believe the best path forward is to continue negotiating with our Republican counterparts in Congress instead," Schumer and Pelosi said in a statement. "Rather than going to the White House for a show meeting that won't result in an agreement, we've asked Leader McConnell and Speaker Ryan to meet this afternoon."

A spokesperson for Speaker Paul Ryan said there were no changes in his schedule to announce.

Congress faces a Dec. 8 deadline to pass stopgap legislation to keep the government open and a slew of other unfinished legislation.

It was hoped the White House meeting might lay a foundation to keep the government running and set a path for a year-end spending package to give both the Pentagon and domestic agencies relief from a budget freeze.

Trump is still seeking his first big legislative win in Congress, and his attack on Democrats came as his marquee tax bill faced turbulence as well.

The White House and top Republican leaders have work to do to get their tax bill in shape before a hoped-for vote later this week. Party deficit hawks pressed for a "backstop" mechanism to limit the risk of a spiral in the deficit, even as defenders of small business pressed for more generous treatment.

At a news conference later in the day, Trump predicted that the Senate tax plan would pass, and accused Democratic leaders of being "all talk" and "no action" for failing to show up for the meeting Tuesday.

On a separate track from taxes is a multi-layered negotiation over several issues. Hoped-for increases for the Pentagon and domestic agencies are at the centre, but a host of other issues are in the mix as well.

A temporary spending bill expires Dec. 8 and another is needed to prevent a government shutdown. Hurricane aid weighs in the balance and Democrats are pressing for legislative protections for immigrants known as Dreamers, even as conservative Republicans object to including the issue in the crush of year-end business.

There's also increased urgency to find money for the children's health program that serves more than eight million low-income children. The program expired on Oct. 1, and states are continuing to use unspent funds. Arizona, California, Minnesota, Ohio, Oregon and the District of Columbia are among those expected to deplete that money by late December or in January.

Democrats carry leverage into the talks, which have Republican conservatives on edge. Republican leaders appear wary of early-stage concessions that might foul the mood of rank-and-file Republicans while the tax bill is in the balance.

Trump's visit to the Capitol is his third in little more than a month. This time, he's trying to make the sale to Senate Republicans on his signature tax bill. Among the holdouts are Republican Trump critics, including Senators Jeff Flake of Arizona and Bob Corker of Tennessee — though Republican leaders are seeking to rope in straggling Republicans with a flurry of deal-cutting.

Trump's sessions with big groups of Republicans tend to take the form of pep rallies, and when visiting a Senate Republican lunch last month, Trump spent much of the time on a rambling account of the accomplishments of his administration.

Trump hasn't engaged much with Pelosi and Schumer since a September meeting that produced an agreement on a short-term increase in the government's so-called debt limit and a temporary spending bill that is keeping the government's doors open through Dec. 8.

Trump revelled in the bipartisan deal for a time and generated excitement among Democrats when he told then he would sign legislation to protect from deportation immigrants who were brought to the country illegally as children.

Trump in September reversed an executive order by former president Barack Obama that gave protections to these immigrants, many of whom have little or no connection to their home country. Shortly afterward, he told Pelosi and Schumer he would sign legislation protecting those immigrants, provided Democrats made concessions of their own on border security.