U.S. President Donald Trump says he would "totally be willing" to partially shut down the government next week if he does not get more funding for a wall along the U.S.-Mexican border to thwart Central American migrants from entering the country.

The U.S. leader, who almost daily unleashes verbal attacks on migrants trying to cross into the United States, told the Politico news site he is insisting that $5 billion for wall construction be included in measures Congress needs to approve to keep several federal agencies open after their current spending authority expires December 7.

Opposition Democrats have said they will approve $1.6 billion for the wall, leaving the two sides far apart. Some Republicans are also opposed to Trump's wall, which he vowed in his 2016 presidential campaign would be paid for by Mexico, although he now wants U.S. taxpayers to foot the bill.

Trump FILE - President Donald Trump listens to a question as he speaks to members of the media on the South Lawn of the White House in Washington, Nov. 26, 2018. FILE - President Donald Trump listens to a question as he speaks to members of the media on the South Lawn of the White House in Washington, Nov. 26, 2018.

"I am firm," Trump said of his $5 billion demand.

"I don't do anything ... just for political gain," Trump said. "But I will tell you, politically speaking, that issue is a total winner. People look at the border, they look at the rush to the police, they look at the rock throwers and really hurting three people, three very brave border patrol folks. I think that it's a tremendous issue, but much more importantly, is really needed. So, we have to have border security."

Trump was referencing a Sunday confrontation at the border in which migrants hurled rocks at U.S. Border Patrol officers, with agents repelling the crowd with blasts of tear gas. Rodney Scott, the chief Border Patrol agent in San Diego, California, just north of the Mexican border, said agents were not seriously injured.

"Their shields and their bulletproof vests actually protected them from the rocks," he said. "We did have a few vehicles that were damaged, some windows and quite a few dents, but none of the agents were seriously injured."

Even as Trump voiced his determination to win congressional approval for the $5 billion in initial funding for a wall estimated to cost more than $20 billion, he told The Washington Post in a separate interview that he could find other ways to build the wall or add more security along the border.

"I think that's been shown better than ever in the last short period of two weeks that we need a wall," Trump told the newspaper. "I see the Democrats are going to want to do something, because they understand, too. Those pictures are very bad for the Democrats. We're not having a wall because of the Democrats. We need Democrat votes to have a wall."

"Now, if we don't get it, will I get it done another way? I might get it done another way," he declared. "There are other potential ways that I can do it. You saw what we did with the military, just coming in with the barbed wire and the fencing, and various other things."

House Speaker Paul Ryan of Wisconsin returns to Ca House Speaker Paul Ryan of Wisconsin returns to Capitol Hill following a meeting with President Donald Trump at the White House, Nov. 27, 2018. House Speaker Paul Ryan of Wisconsin returns to Capitol Hill following a meeting with President Donald Trump at the White House, Nov. 27, 2018.

House Speaker Paul Ryan, leader of the current majority Republican bloc in the House of Representatives, told reporters Wednesday that after the nationwide congressional elections in early November, "hopefully ... Democrats realize that a secure border should not be a Republican thing, it shouldn't be a Democrat thing, it's just good for the country. To actually secure our border. The House is there. We hope the Senate comes with us."

He added, "Turn on the TV, you can see we have a problem at the border. So, we want to secure our border. The House Republicans have always wanted to secure the border, the House Republicans have been passing bills to secure our border, and I'd like to think that Democrats would also want to join us in securing the border, especially after the election."