'Walls work': Trump declares national emergency to build border wall

Washington: President Donald Trump announced on Friday that he will declare a national emergency to fulfil his pledge to construct a wall along the US-Mexico border.

Trump said he will use executive powers to bypass Congress, which approved far less money for his proposed wall than he had sought. He plans to siphon billions of dollars from federal military construction and counter-drug efforts for the wall. The move is already drawing bipartisan criticism on Capitol Hill and expected to face rounds of legal challenges.

"I am going to be signing a national emergency," Trump said from the White House rose garden, as he claimed illegal immigration marked "an invasion of our country".

He said he went through Congress and "made a deal... but I'm not happy with it".

He said legislators had provided more money than he wanted for initiatives such as improving security at ports of entry at the border.

"I don't know what to do with it, we have so much money," Trump said. "But on the wall, they skimped."

In a rare show of bipartisanship, legislators voted on Thursday to fund large swaths of the government and avoid a repeat of the recent, debilitating five-week government shutdown. The money in the bill for border barriers, about $US1.4 billion ($1.9 billion), is far below the $US5.7 billion Trump insisted he needed and would finance just a quarter of the 322 kilometres he wanted this year.

To bridge the gap, Trump announced that he will be spending roughly $US8 billion on border barriers - combining the money approved by Congress with funding he plans to repurpose through executive actions, including the national emergency. The money is expected to come from funds targeted for military construction and counter-drug efforts, but aides could not immediately specify which military projects would be affected.

Despite widespread opposition in Congress to proclaiming an emergency, including by some Republicans, Trump was responding to pressure to act unilaterally to soothe his conservative base and avoid appearing like he's lost his wall battle.

Word that Trump would declare the emergency prompted condemnations from Democrats and threats of lawsuits from states and others who might lose federal money or said Trump was abusing his authority.

In an unusual joint statement, House Speaker Nancy Pelosi and Senate Minority Leader Chuck Schumer, both Democrats, said such a declaration would be "a lawless act, a gross abuse of the power of the presidency and a desperate attempt to distract" from Trump's failure to force Mexico to pay for the wall, as he's promised for years.

"Congress will defend our constitutional authorities," they said. They declined to say whether that meant lawsuits or votes on resolutions to prevent Trump from unilaterally shifting money to wall-building, with aides saying they'd wait to see what he does.

Democratic state attorneys-general said they'd consider legal action to block Trump. Puerto Rico Governor Ricardo Rossello told the President on Twitter "we'll see you in court" if he makes the declaration.

Even if his emergency declaration withstands challenge, Trump is still billions of dollars short of his overall funding needed to build the wall as he promised in 2016. After two years of effort, Trump has not added any new border mileage; all of the construction so far has gone to replacing and repairing existing structures. Ground is expected to be broken in South Texas soon on the first new mileage.

The White House said Trump would not try to redirect federal disaster aid to the wall, a proposal they had considered but rejected over fears of a political blowback.

AP