North Korea's vice foreign minister Monday denied South Korean reports of a sharp increase in ground temperatures at a North Korean nuclear facility.

Chon In Chol spoke during a recess in negotiations with Japanese officials on establishing diplomatic relations between the two countries.The session ended with the two sides deadlocked over Japan's demand that North Korea allow international inspection of its nuclear facilities.

Chon, who heads the North Korean delegation, said Tuesday's talks will focus on bilateral issues, including North Korea's demand for Japanese compensation for 35 years of Japanese colonial rule. The Japanese team said there was little chance for progress without agreement on the nuclear issue.

South Korea's Ministry of Science and Technology said Friday that U.S. satellite data showed temperatures at North Korea's Yongbyon nuclear reactor rose briefly from a normal 50 to 59 degrees to 95 degrees earlier in the week.

U.S. officials said they could not confirm any such increase occurred.

Asked about the reported increase, Chon told reporters, "It is a false report."

The International Atomic Energy Agency in Vienna said Yongbyon is a small research reactor, and that the reported temperature increase was not likely to be the result of a major incident.

North Korea joined the nuclear non-proliferation treaty in 1985 but has refused to let the Vienna-based agency inspect its facilities. It demands that the United States simultaneously allow inspection of its military bases in South Korea, where North Korea claims nuclear weapons are kept.

Chon told a news conference at the North Korean Embassy that the issue could be settled only through talks between North Korea and the United States.

A Japanese Embassy spokesman said Japan did not like to use the word "condition," but that allowing nuclear inspections was "a very important part of the whole process of normalization."