"If we don't get border security after many, many years of talk within the United States, I would have no problem doing a shutdown," Trump said during a joint press conference with Italy's prime minister.

But Trump would not say if he would veto a spending bill in September unless it included "full" funding for a border wall, saying, "I'll always leave room for negotiation." ADVERTISEMENT "I have no red line, unlike President Obama," he added. "I just want great border security." After praising Italian Prime Minister Giuseppe Conte for his hardline stance on immigration, Trump blasted U.S. immigration laws, calling them a “laughingstock” and the “worst” in the world. He put the onus on Congress to change them, saying he would “certainly be willing to close it down to get it done.” The president said he wants Congress to authorize more funding for his long-desired wall at the U.S. southern border and to pass an overhaul of the nation's visa system.

"If we don't get border security, after many many years of talk within the United States, I would have no problem doing a shutdown," Pres. Trump says. https://t.co/7cuzYGzTRS pic.twitter.com/gQmsyinihM — ABC News (@ABC) July 30, 2018

Lawmakers face a Sept. 30 deadline to pass a funding bill and Trump's comments could inflame tensions with GOP leaders, who say they would rather address money for a border wall after the funding deadline passes.

Trump first raised the possibility of a shutdown in a Sunday tweet.

"I would be willing to 'shut down' government if the Democrats do not give us the votes for Border Security, which includes the Wall! Must get rid of Lottery, Catch & Release etc. and finally go to system of Immigration based on MERIT! We need great people coming into our Country!" he wrote.

Trump’s threat of a shutdown came days after Republican leaders in Congress indicated they would be able to avoid such a political standoff.

“The president’s wiling to be patient to make sure that we get what we need so we can get that done,” Ryan said of the border wall funding last Thursday.

McConnell told WHAS Radio last Friday that he believes wall funding will “probably” have to wait until after the November midterms. However, he asserted that a government shutdown is “not going to happen.”

The two chambers of Congress appear at odds in the meantime over how much funding to provide for the wall.

The House Appropriations Committee approved $5 billion for the wall in its Homeland Security bill last week. However, the Senate’s version of the bill includes $1.6 billion to reinforce existing physical barriers.

A shutdown would loom larger over the November midterm elections, where Republicans are attempting to stave off a Democratic push to retake control of the House and Senate.