The Trump administration has made some headway on one of its biggest challenges ahead of President Donald Trump’s meeting with North Korean leader Kim Jong Un later this spring: finding a suitable location for the summit.

A senior U.S. official told NBC News on Wednesday that a number of locations had already been ruled out, including North Korea’s capital, Pyongyang, as well as Beijing and Mongolia, all of which raise security concerns. U.S. officials are instead pushing for a more neutral location, preferably in Europe, with Switzerland among the top choices, the official said.

Trump pledged to step away from the talks if he believes that they are unsuccessful.

"If we don't think it's going to be successful were not going to have it," he said. "If the meeting, when I'm there, is not fruitful I will respectfully leave the meeting."

As UNIAN reported earlier citing The Washington Post, CIA Director Mike Pompeo made a top-secret visit to North Korea over Easter weekend as an envoy for President Trump to meet with that country’s leader, Kim Jong Un, according to two people with direct knowledge of the trip.