The United States is reportedly quietly pursuing diplomatic avenues with North Korea despite repeated pushback from President Donald Trump.

Joseph Yun, a U.S. negotiator with North Korea, has been in contact with officials from Pyongyang’s United Nations mission, a senior State Department official told Reuters on Tuesday.

Yun has stressed to his North Korean counterparts that the regime needs to “stop testing” nuclear bombs and missiles, the official said. North Korea has conducted its sixth nuclear detonation and has fired missiles that could potentially carry a nuclear warhead this year.

The regime may launch a missile while Trump is in Asia this week, according to Newsweek.

When Trump entered the White House, Yun’s objective was to seek the release of U.S. prisoners. The State Department official said now his job is much broader than before.

Though Yun is trying to make progress in his talks with North Korean officials, Reuters reported he has not had high-level talks with anyone from the regime since June when the U.S. secured the release of Otto Warmbier.

Warmbier returned to the U.S. in a coma and died days later. His death iced relations between the U.S. and North Korean contacts, the official said.

Reports of behind-the-scenes diplomacy come despite Trump’s assertions that talks with North Korea are a waste of time. Trump has previously vowed to “totally destroy” North Korea, if it threatened the U.S. or its allies abroad.

Trump is expected to visit Asia beginning Friday. He will be visiting Camp Humphreys, a military base about 40 miles south of Seoul, to highlight the U.S.-South Korean partnership and burden-sharing. He will not visit the Demilitarized Zone, an official told reporters Tuesday.

Trump'strip will take him to Japan, South Korea, China, Vietnam and the Philippines. The president will attend several summits, hold a series of bilateral meetings, be feted at banquets and play golf with Japanese Prime Minister Shinzo Abe.

The Associated Press contributed to this report.