A North Korean envoy says the success of the next round of six-way nuclear talks will depend on whether the United States keeps its promise to end its nuclear threats and provide light-water reactors.

The North's official Korean Central News Agency quoted the remarks by Pyongyang's ambassador to the United Nations, Park Gil-yon, in a letter he sent to the U.N. secretary-general and the General Assembly chairman last Friday.

In the letter, Park said the joint agreement reached at the last round of six-way talks clearly stated not only North Korea's obligations but also those of the U.S. and South Korea.

He said Pyongyang will keep a close eye on U.S. moves concerning the principle of simultaneous "action for action" as agreed on in the joint accord.

The fifth round of the nuclear talks is expected to open around Wednesday in Beijing.