'I will declare an emergency to get border win' - Trump
Donald Trump said he would "100pc" declare a national emergency to build a wall as he visited the Mexico border last night.
The US president said he would "almost definitely" do so if Democrats continued to refuse to give him $5.7bn (€4.95bn) for the wall.
Large parts of America's government have been shut down for 20 days as politicians in Washington failed to agree funding for the proposed barrier.
Mr Trump last night cancelled his planned trip to Davos, Switzerland, for the World Economic Forum on January 22.
Arriving in McAllen, Texas, the president, casually dressed, was greeted by border guards who gave him a security briefing.
McAllen is located in the Rio Grande Valley, the busiest part of the US-Mexico border for illegal crossings.
Moments before Air Force One touched down, it emerged that at least 20 bodies had been found, 17 of them burned, following a gang battle in a town just over the Mexican border.
Outside the US Customs and Border Protection station in McAllen, supporters of Mr Trump chanted "Build that Wall!" while protesters set up a "Trump Baby" blimp. One local supporter of the wall said: "I guarantee everybody out here locks their doors at night."
Sister Norma Pimentel, a nun who runs a church in McAllen where illegal immigrants seek refuge, was set to meet Mr Trump. She hoped he would "better understand the whole reality".
Calling a national emergency would open up new powers for Mr Trump, potentially allowing him to use the defence budget, and military personnel, to construct the wall without approval from Congress.
However, the move would almost certainly be challenged in court by his Democrat opponents, who would accuse him of executive overreach.
Mr Trump said: "I have the absolute right to declare a national emergency.
"The lawyers have so advised me. I'm not prepared to do that yet. But if I have to, I will. I have no doubt about it, I will. I would almost say definitely.
"If you don't have a steel barrier or a wall of some kind - strong, powerful - you are going to have human trafficking, you are going to have drugs pouring across the border, you're going to have the gangs coming in."
Mr Trump dismissed reports that a steel barrier prototype had been easily cut through with a saw during testing, saying that prototype had been designed by a previous administration.
He also denied ever saying that Mexico would "write a cheque" to pay for the border wall, insisting the country would now pay "indirectly" through his renegotiated trade agreement.
It comes as it emerged Mr Trump's former lawyer, Michael Cohen, will testify publicly before Congress next month.
Cohen said in a statement he had accepted an invitation by the panel's Democratic chairman, US Representative Elijah Cummings, to appear publicly before the Committee on Oversight and Government Reform.
"I look forward to having the privilege of being afforded a platform with which to give a full and credible account of the events which have transpired," Cohen said in the statement.
Cohen's testimony before the House Oversight and Reform Committee will be the first major public hearing for Democrats, who have promised greater scrutiny of Mr Trump.
Cohen is a pivotal figure in investigations by special counsel Robert Mueller into potential co-ordination between Russia and the Trump campaign, and by federal prosecutors in New York into campaign finance violations related to hush-money payments to two women who say they had sex with Mr Trump. Mr Trump has denied it.
Cohen has pleaded guilty in both investigations and was sentenced last month to three years in prison.
When asked about the development, Mr Trump told reporters in Texas that he's "not worried about it at all".