WASHINGTON (CBSNewYork) — The most important diplomats at the United Nations took a day trip to the nation’s capital Monday, as President Donald Trump invited members of the security council to the White House for lunch.

Just before taking office, Trump criticized the UN as a “club for people to have a good time.” On Monday, he called the international organization “an under-performer, but it has huge potential,” and told top diplomats they’ll be very busy people with so many danger spots around the globe.

As CBS2’s Tony Aiello reports, the presidency of the security council rotates each month. This month, it’s held by the United States, represented by Ambassador Nikki Haley.

Haley has already been making her mark with tougher talk than most diplomats are used to.

“By its failure, Russia will continue to be isolated,” Haley previously said at the UN. The Russian envoy was among the 14 diplomats invited to the White House for a lunch of halibut and cheese souffle.

The president has a lot on his plate himself, and is counting on the security council to help with Syria and North Korea.

“The council must be prepared to impose additional and stronger sanctions on North Korea’s nuclear and ballistic missile programs,” Trump said Monday. “This is a real threat to the world.”

“We are hosting the members of the security council, and when you think of that, this is the most powerful group that decides sanctions, relief, any sort of conflict that comes up, this is the group,” Haley said at a Monday press briefing. “So the idea of coming to DC is overwhelming for them. They’re extremely pleased.”

The US believes North Korea is ready to hold another nuclear test at any moment, and the rogue nation has now detained American professor Tony Kim.

Chinese President Xi Jinping has called for restraint, and the Trump administration has pushed for “serious talks,” which is why they have sent a carrier strike force to the region.

Meanwhile, the president has promised to release details on a tax reform plan Wednesday as he confronts a looming federal budget showdown that could lead to a partial government shutdown if a deal is not reached by the Friday deadline.

The White House wants funding for the border wall included in the spending bill that must pass by Friday, but it can’t pass without support from eight Senate Democrats who say they’ll never support the border wall.

Senator Charles Schumer (D-NY) has said Democrats won’t vote for a funding resolution that contains money for the wall.

A number of Republicans say Trump should table the wall for next year’s funding fight.

“I think that’s a fight worth having and a conversation and a debate worth having for 2018,” Senator Marco Rubio (R-Fla) said Sunday.

The UN budget is also a concern for the Trump administration; he’s proposed cutting the $1.1 billion the United States currently contributes each year.

He’s said in the past that the budget concerns will go away if the UN starts solving some of the world’s problems. In the meantime, the president has invited all 100 members of the Senate to the White House for a briefing on the North Korean threat on Wednesday.