U.S. Secretary of State Mike Pompeo said on Tuesday there remains "an awful lot of work to do" to achieve the denuclearization of North Korea but he anticipates further progress by the end of next month, when the U.S. and North Korean leaders are expected to meet for a second summit.

Pompeo, addressing the World Economic Forum in Davos via satellite link, said he believed that by the end of February, "We'll have another good marker along the way" with North Korea.

"There remains an awful lot of work to do, but good things have happened already," Pompeo said, referring to a freeze in North Korean nuclear and missile testing since 2017.