He said he had no information on when North Korea might test a ballistic missile again, after the last one two months ago.
The ministry said the duo also noted constructive roles by countries such as China and Russian Federation in resolving the North Korean nuclear issue, and agreed to strengthen strategic communication with other related parties based on close coordination between South Korea and the U.S.
Mattis said the U.S. military was closely watching why there had been no missile launches recently, but declined to give potential reasons for it.
Doan Thi Huong
"I wouldn't speculate on what North Korea's activities are or aren't", White told reporters at the Pentagon Thursday.
The ambassador was speaking at the North Korean mission in Geneva on Friday, as South Korea and the U.S. agreed in Seoul to keep co-operating towards a peaceful end to the crisis.
"Our policy remains to have the verifiable, irreversible denuclearization of the Korean peninsula".More news: WADA rules Russian Federation 'noncompliant'
"We reaffirmed our commitment to continuously engage the Nuclear Weapons States (NWS) and intensify the ongoing efforts of all Parties to resolve all outstanding issues in accordance with the objectives and principles of the SEANWFZ Treaty", it added.
While Washington has said that all options, including military, are on the table in dealing with North Korea, it has stressed its preference is for a diplomatic solution. "We have also discovered a parasite never seen in Koreans before".
Trump, who wants China to play a bigger role in pressuring North Korea to end its nuclear program, reacted to the announcement of the visit by calling it a "big move".More news: Kim Kardashian West having another girl
The US leader just ended a five-nation of Asia, including a stop in Beijing, during which he called for greater diplomatic pressure to be put on North Korea to abandon its nuclear programme.
Representatives from South Korea and the USA agreed yesterday to keep working for a peaceful end to the North Korean nuclear crisis, but a U.S. envoy said it was hard to gauge the reclusive North's intentions as there has been "no signal".
But the "freeze-for-freeze" route seems unlikely as Trump this week rejected that idea, The Associated Press reported.More news: U.S. oil and gas 'resurgence' expected as global demand grows
Asked how China understood Trump's remarks, and if he agreed with Trump's characterization of what Trump said he agreed with Xi, Chinese Foreign Ministry spokesman Geng Shuang said only through talks that addressed all sides legitimate security concerns could there be a peaceful resolution.