Updated

North Korea will make an "important announcement" on Monday amid speculation over the health of its leader Kim Jong Il, a Japanese newspaper reported Sunday.

The 66-year-old North Korean leader disappeared from public view in mid-August and failed to make appearances on two important national holidays, leading to speculation he was seriously ill. U.S. and South Korean officials said he suffered a stroke and had brain surgery, but North Korea has denied he is ailing.

Quoting unidentified sources at Japan's defense ministry, the Sankei said Tokyo had information that "there will be an important announcement on (Oct.) 20th."

The Sankei said there was speculation within the Japanese government that the North's announcement could be about Kim's death or a government change induced by a coup.

North Korea will also ban foreigners from entering the country starting Monday, it said, without giving further details.

Japanese defense and foreign ministry officials could not be reached for comment Sunday.

The Sankei report came a day after Japan's biggest-selling Yomiuri daily said North Korea had ordered its diplomats abroad to be on standby for an important announcement.

Quoting several unidentified sources, the Yomiuri said Saturday the announcement could be about Kim's health or North Korea's relations with neighboring South Korea.

In Seoul, Kim Ho-nyeon, chief spokesman at the South Korean Unification Ministry, said Sunday the ministry could not confirm the Yomiuri report.

Kim said the ministry had not detected any unusual signs in North Korea.

South Korea's National Intelligence Service said it was trying to verify the Japanese media reports.

The Sankei also said the Chosen Soren, a pro-Pyongyang association of Koreans living in Japan, told its top officials to halt foreign and domestic trips. The Chosen Soren functions as North Korea's de facto embassy in Japan as Pyongyang and Tokyo have no diplomatic ties.

North Korea released photos earlier this month showing Kim inspecting a military unit and appearing healthy. However, it did not say when the pictures were taken. Some analysts said the photos appeared to have been taken earlier because plant foliage was wrong for the time of year.

On Thursday, North Korea threatened to break off all relations with South Korea if its new conservative government continues what the North called a policy of reckless confrontation with the communist nation.