WASHINGTON — US President Donald Trump bitterly attacked top Democrat Nancy Pelosi on Sunday and she again insisted that he end the government shutdown before border security talks can begin, but there were hints of possible movement.

Trump lashed out on Twitter a day after Pelosi, speaker of the House of Representatives, dismissed as a "non-starter" his offer to extend temporary protection to about a million immigrants in return for US$5.7 billion for the wall he wants on the Mexican border to fulfill a signature campaign promise.

Government shutdowns are a disruptive political ritual that have occurred in various administrations and are almost unique to the American system. But this one is the longest on record. It has left about 800,000 federal workers unpaid -- among them airport security officers, FBI agents, museum workers, and Coast Guard members.

"Nancy Pelosi has behaved so irrationally & has gone so far to the left that she has now officially become a Radical Democrat," the president tweeted.

"She is so petrified of the ’lefties’ in her party that she has lost control."

It was Trump’s most direct attack on Pelosi since the partial government shutdown began, and appeared to reflect a mounting sense of frustration.

Pointedly ignoring his personal comments, Pelosi on Twitter emphasised the need to end the impasse, which has inflicted increasing pain after one month, with some government employees having to turn to food banks or local charities to get by.

"Reopen the government, let workers get their paychecks and then we can discuss how we can come together to protect the border. #EndTheShutdown," she tweeted.

- ’Good-faith compromise’ -

While Pelosi and other Democrats dismissed Trump’s offer, Republicans insisted that it represented actual movement by the president.

Vice President Mike Pence, who has been leading the administration’s contacts with Congress, said the Senate would put the proposal to a vote as early as Tuesday. He called it "a good-faith compromise."

The planned vote also reflects a shift by Senate Republican leader Mitch McConnell. He insisted previously that he would not take up any shutdown bill unless both Trump and Democratic leaders backed it.

"In a very real sense, what President Trump did here was he set the table for a deal," Pence said on "Fox News Sunday."

The bill’s fate was far from clear. Republicans hope to lure the votes of a few Democrats from Trump-friendly states to reach the 60 votes needed, but they may lose some hard-line conservatives in the process.

- Most blame Republicans -

The Trump administration -- increasingly blamed by Americans for the shutdown -- is trying to balance demands of those hard-liners and Democrats who adamantly oppose spending the $5.7 billion Trump wants for a wall.

Trump has regularly warned of what he says is a serious criminal threat from undocumented migrants entering the country, which is grappling with a surge in arrivals by families and children who say they are fleeing poverty and violence in Central America.

Democrats have offered more than $2 billion for a range of other border-security measures.

They assailed Trump’s new offer as cynical, noting that it was the president who -- by moving earlier to end the DACA program protecting 700,000 young immigrants and to expel about 300,000 others in a separate program – had placed in jeopardy many of those for whom he now offers temporary protection.

But anti-immigrant voices also attacked Trump’s offer as tantamount to amnesty for the undocumented -- a toxic concept for many conservatives.

"No, Amnesty is not a part of my offer. It is a 3 year extension of DACA," Trump said in another tweet. DACA was former president Barack Obama’s program to shield undocumented immigrants who entered the country as children.

Trump said that there would be "no big push" to remove the 11 million people in the country illegally, before warning: ’but be careful, Nancy!"

His immigration crackdown has not stanched the influx of migrants, and a new group of about 400 Hondurans -- the fourth since October 13 -- headed north on Saturday, officials there said.

Still, as the costs of the US shutdown mounted, both sides in the standoff appeared to be casting about cautiously for a road ahead.

"The vote this week (in the Senate) is not to pass the bill," said Senator James Lankford, a Republican, "It’s to open up and say, can we debate this? Can we amend it? Can we make changes? Let’s find a way to get the government open."

Representative Bennie Thompson, a Democrat who chairs the Homeland Security Committee, said that "I would not rule out a wall in certain circumstances."

He suggested that Democrats were amenable to negotiating if Trump would stop demonising the party and its leaders and provide assurances that he would not suddenly shift positions.

"The notion that we have come from a (focus on a) wall to some other thing is moving it along," he told ABC’s "This Week," "but we have to sit down and talk."

Representative Tulsi Gabbard, who plans to seek the presidency in 2020, told CNN it was urgent that both sides "come together and have a real conversation and hash out the differences."

But Representative James Clyburn, the third-ranking House Democrat, insisted that the government must first be reopened. — AFP