Vice President Kamala Harris waits outside her official residence, Sept. 16, in Washington. AP-Yonhap

North Korea may well conduct a nuclear test during U.S. Vice President Kamala Harris' upcoming trip to Japan and South Korea as Pyongyang has been preparing for such a test, a senior U.S. administration official said Friday.

The official warned the North will face serious consequences should it choose to conduct a new test.

"It is possible and we previously said that the DPRK is preparing to conduct a nuclear test," the official said when asked about the possibility of a North Korean nuclear test during Harris' trip to the Northeast Asian countries next week.

DPRK stands for the Democratic People's Republic of Korea, North Korea's official name.

The official noted Pyongyang has been said to be preparing for a nuclear test for some time.

"We have made clear that such a test would result in additional actions by the United States to demonstrate our ironclad commitment to the security of the Republic of Korea and to our Japanese allies," said the official, referring to South Korea by its official name.

"We have made clear how concerned we have been by North Korean provocations and destabilizing behavior and a nuclear test would certainly be in that category," the official added, also noting the issue of North Korean provocations will "certainly" be discussed when the U.S. vice president meets her South Korean counterparts.

The vice president is scheduled to make a four-day visit to Japan from Monday, leading a presidential delegation to the funeral of former Japanese Prime Minister Shinzo Abe.

She will arrive in South Korea on Thursday for a meeting with South Korean President Yoon Suk-yeol, the official said in a telephonic press briefing. It will mark her first trip to both Japan and South Korea since taking office early last year.