Hwang Jang-yop, the highest-ranking North Korean official ever to defect to South Korea, has spent his second day in Washington.

Details of his itinerary are being kept under tight wraps for security reasons.

During his ten-day stay in the United States, Hwang is expected to meet Undersecretary of State for Arms Control and International Security John Bolton and Assistant Secretary of State for East Asian and Pacific Affairs James Kelly. He'll also meet Senator Sam Brownback and Rep. Henry Hyde, the chairman of the House International Relations Committee.

On Friday, Hwang is scheduled to speak about political and human rights situations in his former communist homeland at a forum sponsored by the Defense Forum Foundation, which invited him to speak in the U.S.

This is Hwang's first overseas trip since his defection to South Korea in 1997.

Hwang formerly served as a secretary of the North Korean Workers' Party and is known as the architect of North Korea's juche, or self-reliance, ruling theory.

The former party secretary's previous attempts to visit the United States were discouraged because of Seoul's concern that his criticism of Pyongyang could derail burgeoning inter-Korean reconciliation.