Sources close to the Japanese Prime Minister say he plans to step down to deal with a health problem.
Abe Shinzo is scheduled to hold a news conference later in the day to explain his decision.
NHK has learned Defense Minister Kono Taro is arranging a meeting with his US counterpart, Mark Esper, in the US territory of Guam this month.
Sources say Kono is planning to fly to Guam by an Air Self-Defense Force plane on August 29 for talks with Esper at a US Air Force base.
The Russian emergencies minister has visited one of the four Russian-held islands claimed by Japan, and stressed Moscow's intention to develop the area. Tokyo has lodged a protest against the visit.
Yevgeny Zinichev attended the opening ceremony of an emergency rescue center on Kunashiri Island on Wednesday.
Japan's health minister Kato Katsunobu has hinted at the possibility of another nationwide state of emergency if infections of the novel coronavirus surge.
Kato told reporters on Tuesday that he is aware local authorities are taking measures to contain infections. But he said the government could declare another state of emergency if the number of cases rises rapidly despite such efforts.
Japan's disaster management minister says areas stricken by torrential rains are suffering from a lack of volunteers to help the cleanup.
Takeda Ryota appeared on a NHK program on Sunday. He said that the number of people who have come forward to volunteer has been very low, because of concerns over the coronavirus.
Tokyo prosecutors have indicted former Justice Minister Kawai Katsuyuki and his lawmaker wife Kawai Anri on charges of buying votes for an election.
Prosecutors say Kawai Katsuyuki handed out a total of around 270,000 dollars to about 100 people, mainly local politicians and supporters. They say he tried to secure votes for his wife's successful bid for the Upper House last July.
Prosecutors in Tokyo are expected to indict Lower House lawmaker and former Justice Minister Kawai Katsuyuki, along with his wife, Upper House member Kawai Anri, on charges of election law violations on Wednesday.
The prosecutors believe the couple gave about 270,000 dollars in cash to about 100 local politicians and supporters. They think the aim was to secure votes last July for the wife, who won her seat.
Investigative sources have told NHK that a former Japanese justice minister apparently deleted potential evidence of vote-buying after a magazine published an article about his alleged election law violation.
Prosecutors arrested Kawai Katsuyuki and his lawmaker wife Kawai Anri on Thursday for giving cash to local politicians and others in an Upper House election in which she ran successfully last July.
Economic Revitalization Minister Nishimura Yasutoshi canceled a news conference and worked from home on Saturday as an official of the Cabinet Secretariat was found to have contracted the new coronavirus.
The government said on Friday that the man in his 40's is a member of the taskforce launched last month to deal with the pandemic.
A Japanese government minister has expressed concern that efforts against the coronavirus may be insufficient.
Economic Revitalization Minister Nishimura Yasutoshi was speaking at a meeting of a government panel of experts on Wednesday. Nishimura is in charge of anti-coronavirus measures.
The Japanese minister in charge of coronavirus measures has called for further efforts to reduce social contact by up to 80 percent to contain the spread of the virus.
Economic Revitalization Minister Nishimura Yasutoshi said on an NHK program on Sunday that there have been fewer people going out in areas covered by the state of emergency.
Japan's minister in charge of coronavirus measures has warned of additional restrictions if the current efforts to reduce social contact are found to be inadequate.
Nishimura Yasutoshi made the remark during a teleconference with the leaders of major business organizations on Thursday.
Japan's Prime Minister Abe Shinzo is explaining his decision to declare a state of emergency to members of the Lower and Upper chambers of the Diet.
The coronavirus outbreak has pushed the government to issue fresh measures for Tokyo and six other prefectures.
Japan's health minister says local governments should consider asking people with mild symptoms of the coronavirus to self-isolate at their homes or in hotels.
Kato Katsunobu told reporters on Friday that the ministry will allow local governments to decide whether people with mild or no symptoms should be hospitalized. It wants to give priority to seriously ill patients in Tokyo and other areas where the number of cases is rapidly increasing.