President Trump again threatened to shut down the federal government over border security funding if Congress doesn't act. Sunday, he blamed congressional Democrats for failing to support his administration's immigration policies.

"As far as the border is concerned and personally, if we don't get border security after many, many years of talk, I would have no problem doing a shutdown. It's time we had proper border security, we're the laughing stock of the world," he said during a joint press conference with Italy's Prime Minister Giuseppe Conte on Monday. He told Conte that "strong nations must have strong borders. We have a solemn obligation to protect our citizens and quality of life."

Earlier Monday, during the leaders' Oval Office meeting, Mr. Trump commended Conte for Italy's immigration policies.

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"Italy has taken a very firm stance on the border, a stance that few countries have taken," Mr. Trump said. He added, "frankly you're doing the right thing in my opinion."

But Mr. Trump also told reporters that he'll "always leave room open for negotiation" with Congress, saying he has "no red line" to immigration proposals, but ultimately just wants "great border security."

Conte was the latest member of the European Union to hold meetings with the president amid ongoing trade negotiations over existing tariffs. Conte's visit follows that of European Commission President Jean-Claude Juncker, who agreed to work with Mr. Trump towards "zero tariffs" between the U.S. and EU.

Mr. Trump highlighted his "breakthrough" agreement with Juncker on trade, saying that "now is the perfect time to expand commerce between the U.S. and Italy." Conte agreed, saying that the agreement reached is "fundamental" to achieving a "more equitable trade relationship," urging the partners to "work on it immediately."

And on Iran, Mr. Trump said that he would be willing to meet with Iran's President Hassan Rouhani in light of other "great" meetings with known adversaries including Russian President Vladimir Putin and North Korean dictator Kim Jong Un. "I'll meet with anybody I believe in meeting," he said. Mr. Trump set "no preconditions" for a potential meeting with Iranian leaders, saying, "If they want to meet, I'll meet."

The idea of a sit-down meeting was raised by a reporter during the joint news conference, and it came after Mr. Trump warned Rouhani last week that he would face dire consequences if he threatened the U.S. again. Mr. Trump earlier this year pulled the U.S. out of the international nuclear deal meant to prevent Tehran from developing a nuclear weapon and ordered increased American sanctions.