North Korea may make an "important" announcement on Tuesday, amid rumours that reclusive leader Kim Jong-Il has fallen seriously ill, Japanese media reports.
Japan's Sankei Shimbun newspaper, quoting an unnamed defence ministry source, said that an "announcement of important information will be made on October 20."
"It is not clear whether the set of information is related to the health of Kim," the newspaper said.
North Korea could move to ban foreigners from entering the Stalinist state from Monday, the paper said.
The Japanese Foreign Ministry declined to comment on the report, which cited unsubstantiated rumours that secretive North Korea could announce Mr Kim's death or a change in leadership after a coup.
Reports of his illness surfaced after he failed to appear at the country's 60th anniversary parade on 9 September. South Korean officials have said he underwent brain surgery as a result of a stroke in mid-August.
North Korean state television aired photographs a week ago of Mr Kim inspecting a women's artillery base, although a United States official doubted that the images were recent.