WASHINGTON • The partial United States government shutdown entered a record 22nd day yesterday, as President Donald Trump remains steadfast in his demand for US$5.7 billion (S$7.7 billion) to build a Mexico border wall and Democrats in Congress are determined to refuse him the funds.

The impasse has paralysed Washington, with the President retaliating by refusing to sign off on budgets for swathes of government departments unrelated to the dispute. As a result, 800,000 federal employees as diverse as FBI agents, air traffic controllers and museum staff did not receive pay cheques on Friday.

The shutdown became the longest on record at midnight on Friday, when it overtook the 21-day stretch in 1995-1996, under Mr Bill Clinton.

Mr Trump on Friday however backed off on a series of previous threats to end the deadlock by declaring a national emergency and attempting to secure the funds without congressional approval.

"I'm not going to do it so fast," he said at a White House meeting.

Mr Trump described an emergency declaration as the "easy way out" and said Congress had to step up to the responsibility of approving the US$5.7 billion needed.

"If they can't do it... I will declare a national emergency. I have the absolute right," he said.

Until now, the President had suggested numerous times that he was getting closer to taking the controversial decision. But Mr Trump himself acknowledged in the White House meeting that an attempt to claim emergency powers would likely end up in legal battles going all the way to the Supreme Court.

Opponents say that a unilateral presidential move would be constitutional overreach and set a dangerous precedent in similar controversies.

The stand-off has turned into a test of political egos, particularly for Mr Trump, who came into office boasting of his deal-making powers and making an aggressive border policy the keystone of his nationalist agenda.

Democrats, meanwhile, seem determined at all costs to prevent a president who relishes campaign rally chants of "build the wall!" from getting a win.

Both Democrats and Republicans agree that the US-Mexican border presents major challenges, ranging from the violent Mexican drug trade to the plight of asylum seekers and poor migrants seeking new lives in the world's richest country. There is also little debate that border walls are needed: about a third of the frontier is already fenced off.

But Mr Trump has turned his single-minded border wall push into a political crusade seen by opponents as a stunt to stoke xenophobia in his right-wing voter base, while wilfully ignoring the border's complex realities.

For Mr Trump, who visited the Texas-Mexico border on Thursday, the situation amounts to an invasion by criminals that can only be solved by more border structures.

Separately, Puerto Rico's governor urged Mr Trump to not redirect emergency funds destined to the island instead for the border wall. Mr Ricardo Rosello's plea followed reports the White House has asked the Army Corps of Engineers to look into ways to divert funds destined for natural disaster relief for the wall.

"No wall should be funded on the pain and suffering of US citizens who have endured tragedy and loss through a natural disaster," Mr Rosello tweeted on Friday. "Today it's us, tomorrow it could be you."

In September 2017, Hurricane Maria tore through the US territory in the Caribbean, killing some 3,000 people, causing catastrophic material damage and crippling the island's power grid for months.

AGENCE FRANCE-PRESSE