NEW YORK/SEOUL/BEIJING -- A senior United Nations official embarked on a rare trip to North Korea on Tuesday amid heightened tensions over Pyongyang's recent long-range missile test.

Jeffrey Feltman, undersecretary general for political affairs, will discuss "issues of mutual interest and concern" with North Korean Foreign Minister Ri Yong-ho and others, UN spokesman Stephane Dujarric said Monday. He plans to stay for four days.

"The visit is in response to a longstanding invitation from the authorities in Pyongyang for policy dialogue with the UN," he told reporters, according to multiple news reports. "It will be a wide-ranging discussion."

Feltman's visit comes a week after North Korea test-fired a new intercontinental ballistic missile apparently capable of striking anywhere on the US mainland.

The North declared that it has completed its "state nuclear force" with the latest Hwasong-15 test.

He will meet with North Korean government officials, UN officials and the diplomatic corps there, the spokesman said.

Feltman boarded a North Korean Air Koryo flight for Pyongyang at Beijing's airport. He made no comment when asked by reporters for details about his trip.

Feltman's trip marks the first high-ranking visit by a UN official to North Korea since his predecessor Lynn Pascoe traveled to the North in February 2010 and former UN humanitarian chief Valerie Amos went there in October 2011.

Former UN Secretary-General Ban Ki-moon planned to visit the now-shuttered inter-Korean industrial complex in North Korea's border city of Kaesong in May 2015, but the North abruptly canceled its approval for the trip.

Experts expect that Feltman's visit may set the tone for Pyongyang to come to the negotiation table.

UN Secretary-General Antonio Guterres has expressed his willingness to serve as a mediator to resolve the problem of North Korea's nuclear and missile programs.

South Korea's foreign ministry welcomed the move, hoping that the trip will help deliver the international community's wish for the North to stop provocations and threats, and take the path toward denuclearization.

Seoul's unification ministry also voiced hope that Feltman's trip could help the North change its course.

"We hope that the visit can pave the way for North Korea to come to dialogue," said a ministry official said, asking not to be named. (Yonhap)