President Donald Trump has said he has “no idea” whether he can get a deal with House Speaker Nancy Pelosi for his border wall as the partial US government shutdown slipped into the record books.

The president did not tip his hand on Saturday on whether he will move ahead with an emergency declaration that could break the impasse, free up money for his wall without congressional approval and kick off legal challenges and a political storm over the use of that extraordinary step.

A day earlier, he said he was not ready to do it “right now”.

Politicians are due back in Washington from their states and congressional districts in the new week.

Mr Trump fired off a series of tweets pushing back against the notion that he does not have a strategy to end what became the longest government shutdown in US history when it entered its 22nd day on Saturday.

“Elections have consequences!” he declared, meaning the 2016 election in which “I promised safety and security” and, as part of that, a border wall.

Mr Trump threatened anew that the shutdown could continue indefinitely as the Democrats, who now control the House, refuse to give him money for the wall.

Later on Saturday, he telephoned Fox News Channel’s Justice with Judge Jeanine Pirro from the White House.

Ms Pirro pressed Mr Trump on why he had yet to declare a national emergency. He said he was giving Congress a chance to “act responsibly”.

The president is expected in the new week to sign legislation passed by Congress to provide back pay for some 800,000 federal workers who are not being paid during the shutdown.

Secretary of State Mike Pompeo, travelling in Abu Dhabi, claimed that morale is good among US diplomats even as many work without pay.

“We’re doing our best to make sure it doesn’t impact our diplomacy,” he said.

Almost half of the State Department employees in the US and about one-quarter abroad have been granted a leave of absence during the shutdown.

With the exception of certain local employees overseas, the rest are working without pay, such as those tasked with supporting Mr Pompeo’s trip, which has thus far taken him to Jordan, Iraq, Egypt and Bahrain.

Government Shutdown
Snow falls on the White House as a winter storm arrives in the region during the longest government shutdown in US history (Alex Brandon/AP)

An emergency declaration by Mr Trump could break the stalemate by letting him use existing, unspent money to build the US-Mexico border wall, without needing congressional approval.

Democrats oppose that step but may be unable to stop it and many Republicans are wary too.

Nevertheless the administration has accelerated planning for it.

Officials explored diverting money from a range of accounts, including 13.9 billion dollars given to the Army Corps of Engineers after last year’s deadly hurricanes and floods, but that option appeared to lose steam following an outcry.

Other possibilities included tapping asset forfeiture funds, such as money seized from drug kingpins, according to a congressional Republican.

The White House also was eyeing military construction money, another politically difficult choice because it would take away from a backlog of hundreds of projects.