US President Donald Trump showed no signs of budging on his demand for border wall funding on Wednesday, the 12th day of a partial federal government shutdown.

The shutdown, which began on December 22, was triggered by the Republican president's demand for more than $5bn to fund a wall on the US's southern border.

Congressional leaders emerged from a closed-door meeting with Trump on Wednesday without a resolution. They are expected to return to the White House for talks on Friday, signalling the shutdown will likely stretch into the weekend.

During Wednesday's meeting, top Democrats said they pressed Trump to explain why he wouldn't end the shutdown.

"I said, Mr President, give me one good reason why you should continue your shutdown," Senate Minority Leader Chuck Schumer said after the meeting. "He could not give a good answer."

After the meeting, Trump tweeted that he remained "ready and willing to work with Democrats".

Earlier on Wednesday, the president told reporters that the shutdown could last a "long time", adding that the wall is "too important of a subject to walk away from".

"I think the people of this country think I am right," Trump said, and it "could be a long time" before the government reopens.

Trump also rejected his own administration's offer to accept $2.5bn for the wall. That offer was made when Vice President Mike Pence and other top officials met Schumer at the start of the shutdown.

At Wednesday's meeting, senior Department of Homeland Security officials spoke to congressional leaders about border security. Democratic leaders reportedly cut off Homeland Security Secretary Kirstijen Neilsen and tried to no avail press Trump to accept their offer.

181210211443443

Incoming House Minority Leader Kevin McCarthy told reporters that officials did not finish the briefing and that Trump requested the top Republicans and Democrats return on Friday to continue the meeting.

"The president asked us to come back on Friday after the leadership races" for the new session of Congress, McCarthy said. "We know that we have a challenge along the border. We want to solve that issue. We want to make sure we open this government up. And I think at the end of the day, the president, listening to him, he wants to solve this as well," he said.

House Democrats' plan

It was unclear if the briefing would lead to a breakthrough in the standoff over a funding dispute.

When Democrats, led by presumptive House Speaker Nancy Pelosi, take over the House on Thursday, they plan to approve a two-part spending package meant to end the shutdown. But its prospects of passage are grim in the Senate, where Republicans hold a majority.

190102082249473

The House Democrats' measure does not contain the $5bn Trump wants for the wall - one of his key campaign promises - and sets up the first major battle of the new Congress between House Democrats led by Pelosi and Republican Senate Majority Leader Mitch McConnell.

The Democrats' two-part package includes a bill to fund the Department of Homeland Security at current levels through February 8 and provide $1.3bn for border fencing and $300m for other border security items including technology and cameras.

The second part of the package would fund federal agencies that are now unfunded, such as the Justice, Commerce and Transportation departments, through September 30.

At the Capitol on Wednesday, Pelosi said she hoped Republicans and the White House “are hearing what we have offered” to end the shutdown.

Later in the day, McConnell said the Senate would not consider the bills, calling them a "political sideshow".

The White House had previously dismissed the Democrats' proposal as a "non-starter".

"It does not fund our homeland security or keep American families safe from human trafficking, drugs, and crime," White House Press Secretary Sarah Sanders said in a statement late on Tuesday.

181226191428885

Trump remains committed to "an agreement that both reopens the government and keeps Americans safe," she said.

Trump said last month he would be "proud" to shut down the government over the issue but then blamed Democrats.

Tough position

Trump says the wall is crucial to curbing irregular immigration. Democrats disagree, with Pelosi calling the wall immoral, ineffective and expensive. Trump repeatedly said during his presidential campaign that Mexico would pay for the wall, but Mexico has refused and US taxpayers likely will be left footing the bill.

The Democratic package could put Trump and his Republican allies in a tough position. If they reject funding bills for departments unconnected to border security, Republicans could be seen as holding those agencies and their roughly 800,000 affected workers hostage to Trump's desire to build a wall.

More than half are working without pay, while the rest are furloughed.

190101101116332

Last week, federal employees sued the US government over the requirement that workers deemed "essential" must work without pay during the shutdown.

In the past, Congress has approved back pay for federal workers, but the American Federation of Government Employees, which announced the lawsuit on Monday, called the requirement to work without pay "inhumane".

On Wednesday, the Smithsonian museums and National Zoo in Washington, DC, closed due to the shutdown.