NEW YORK   -   US President Donald Trump has cancelled his planned trip to the World Economic Forum in Davos, Switzerland, citing the prolonged government shutdown, while re-asserting his willingness to declare a national emergency to pay for building his promised 3,145 km-long wall along the border with Mexico aimed at stopping illegal migration.

The announcement was made in a tweet Friday in which Trump blamed Democrats for the shutdown, which began on December 22 after he and his fellow Republicans failed to come to an agreement with Democrats on whether to allocate more than $5 billion in funding the president has been demanding for the border wall.

Democrats, who control the House of Representatives blame Trump for the shutdown, as they oppose the wall, calling it ineffective, immoral and expensive. They have instead agreed to allocate more than $1.3 billion in funding for broader border security measures that do not include a wall.

Earlier on Thursday, Trump said he wanted to go to the annual Davos event, which is scheduled from January 22 to 25, but would skip the meeting if the shutdown persisted. He then made the announcement he was cancelling his trip to Switzerland.

In his tweet, the president also offered his “warmest regards and apologies” to the organizers of the gathering of world leaders and global elites.

The announcement came on the shutdown’s 20th day, with no end in sight to the funding impasse. Trump stormed out of a meeting with top Democrats on Wednesday, calling it a “waste of time” because they denied his request for border wall money.

White House officials for days have weighed scrapping the trip. Presidential travel abroad is logistically daunting under normal circumstances and even more so without several key aides to do advance and planning work because they were furloughed due to the shutdown.

Trump’s team was also wary of the optics of the president hobnobbing with billionaires and financiers while hundreds of thousands of federal workers back home go without pay. The president referred to those discussions earlier Thursday while speaking to reporters before leaving the White House for a trip to the U.S.-Mexico border.

 “Well, I intended to go and speak in front of the world financial community in Davos. That’s still on. But if the shutdown continues — which is in a while from now — but if the shutdown continues, I won’t go,” he said.

The president was set to travel with a large entourage to the annual gathering, a group that reportedly included his daughter and senior adviser Ivanka Trump and Homeland Security Secretary Kirstjen Nielsen, whose agency is responsible for policing the border that Trump argues is in “crisis.”

The U.S. delegation’s head, Treasury Secretary Steven Mnuchin, is still expected to attend the gathering in Trump’s absence, multiple media outlets reported.

Other officials expected to travel to Davos include Secretary of State Mike Pompeo, Commerce Secretary Wilbur Ross and U.S. Trade Representative Robert Lighthizer.

Trump spent most of the day in Texas near the US-Mexico border to draw further attention to his case after negotiations with Democrats failed to make progress.

Asked about a national emergency declaration, Trump said as he left the White House on Thursday, “I’m not prepared to do that yet, but if I have to I will.” He contends such a declaration would allow him to direct the military to begin wall construction.

In a sign of growing unease about the partial government shutdown, some Senate Republicans came off the sidelines to hash out a deal that would reopen the government as Congress worked toward a broader agreement tying wall funds to protection for some undocumented immigrants and other migrants.

But before those negotiations could gain momentum, they collapsed. Vice President Mike Pence and other members of  Trump’s team let it be known privately that the president would not back such a deal.

  Meanwhile, the Washington Post reported that White House is laying the groundwork for declaring a national emergency that would let President Trump build a section of  the wall, possibly using funds from the Army Corps of Engineers.

  NBC News, in a similar report, said the plan called for building  a section of the border barrier by declaring an emergency and tapping a $13.9 billion Army Corps fund that was set aside for U.S. disaster relief and prevention projects.

Such a strategy would escalate a wall-funding standoff between Trump and Democrats in Congress from a policy dispute to a test of presidential power and likely trigger a legal challenge, experts said.