South Korean Foreign Minister Yun Byung-se will travel to Washington next week for consultations on North Korea and bilateral issues in the run-up to a visit here by President Park Geun-hye in May, an informed source said Monday.

"Minister Yun is scheduled to visit Washington in the first week of April," the source said on the condition of anonymity.

Yun will meet with Secretary of State John Kerry, mainly to discuss agenda items for the first summit talks between Park and her American counterpart, Barack Obama, in early May, according to the source.

Yun's trip plan is deemed unusual as Kerry plans to visit Seoul next month, meaning they will have two separate meetings in as many weeks.

"There is a shared view that Yun had better make his first trip to the U.S. as South Korea's foreign minister in advance of President Park's visit," the source said. "Given President Park's schedule, it's hard to find another time for Yun's visit."

The offices of Yun and Kerry are expected to make simultaneous announcements of the minister's visit, the source said.

About a week ago, Kerry called Yun to congratulate him on his appointment as foreign minister.

"The secretary and foreign minister confirmed that the U.S.-ROK (South Korea) alliance has never been stronger... They also discussed missile defense and the DPRK (North Korea)'s recent provocative actions and rhetoric," State Department spokesman Patrick Ventrell said at the time.

Meanwhile, South Korea's chief nuclear envoy, Lim Sung-nam, is also considering a trip to Washington next week for a meeting with Glyn Davies, U.S. special representative for North Korea policy, another diplomatic source said. (Yonhap News)