WASHINGTON - After a weekend of talks between White House officials and Democratic lawmakers, U.S. President Donald Trump on Sunday showed no signs of yielding to pressures or giving up his demand funding the construction of a physical barrier on the U.S.-Mexico border.

Trump tweeted in the evening that his administration is now planning to build a “steel barrier” rather than “concrete” wall on the southern border following what he said was a “productive” meeting during the day between Vice President Mike Pence and congressional Democratic staffers.

Heading to Camp David in Maryland for a meeting with White House staff, Trump told reporters that he will not give up the border barrier, which is one of his primary presidential campaign promises in 2016. “There’s not going to be any bend there,” he said.

The border wall issue was also among the topics at the Camp David meeting, according to media reports. Upon returning to the White House in the afternoon, Trump told reporters he had told his aids to use the term “steel barrier” instead of concrete wall because the Democrats “don’t like concrete, so we’ll give them steel.”

Disputes between the White House and Democratic lawmakers over the wall led to a federal budget deadlock that triggered a partial government shutdown, which is entering the third week. The Democrats, who gained more leverage in the fight after seizing House majority Thursday, also pledged to strengthen border security, but view the wall as immoral and ineffective. They agreed to offer 1.3 billion U.S. dollars for border security, not the wall.

Trump declared in the morning that he can hammer out a deal with Democratic leaders “in 20 minutes, if they want to,” adding that if they are unwilling to reach an agreement, the shutdown is “going to go on for a long time.”

Pence and his group held talks Saturday through Sunday with representatives of House Speaker Nancy Pelosi and Senate Minority Leader Chuck Schumer, both of whom are Democrats, to find solutions for reopening the government.

“During our meetings with congressional staff this weekend, we made it clear that we have a crisis on our southern border, and we outlined the president’s plan to secure our border, build a wall, and protect the American people,” Pence said after the Sunday meeting.

For the part of the Democratic Party, Schumer on Sunday suggested treating the effort to end the shutdown and the debate on border security separately, adding that the longer the shutdown drags on, the bigger the pressure will grow.

In addition, Schumer told reporters in New York that “a growing number of Republicans” are joining the Democrats in calling for solutions to reopen the government, according to U.S. media. Senate Majority leader Mitch McConnell last week kicked the ball to the Democrats’ side as his spokesman said the Senate will not pass any bill that the president won’t sign.

Pelosi said she is prepared to begin passing individual bills in the coming days to resume the function of federal agencies shut down due to a lapse in appropriations. She and Schumer said in a statement last week that “it would be the height of irresponsibility and political cynicism of the Senate Republicans” to block the Democrats’ effort to reopen the government.

Trump said earlier Sunday that he expects “some very serious talks (to) come Monday, Tuesday, Wednesday,” but, according to media reports, one Democratic official familiar with the Pence-Democrats meeting said no further discussions were scheduled yet.