Tokyo (CNN) -- The newly appointed Japanese ambassador to China has been hospitalized after collapsing in Tokyo, Japanese authorities said Thursday, just two days after he was named to the post amid high tensions between the two countries.
Shinichi Nishimiya, 60, was taken to a hospital because of his "health condition," the Japanese Foreign Ministry said without disclosing further details on what had happened.
Previously a deputy minister for foreign affairs, Nishimiya is due to replace the current Japanese ambassador in Beijing, 72-year-old Uichiro Niwa, in the coming weeks.
Nishimiya was found collapsed, the Tokyo Metropolitan Police said without providing details on who found him or precisely where.
He is scheduled to take up the high-profile post at a difficult time for relations between Tokyo and Beijing.
The Japanese government's purchase this week of a set of disputed islands in the East China Sea from a private owner has angered China, which has called the acquisition "illegal and invalid."
The Chinese authorities said Tuesday that they had sent two maritime surveillance ships to waters near the islands, which are currently under Japanese control.
Beijing says it has an "action plan for safeguarding the sovereignty" of the islands, which it calls Diaoyu and Tokyo calls Senkaku.
The Japanese government's move to bring the islands under public ownership has prompted increasingly aggressive words from the Chinese authorities and news media.
Hong Lei, a spokesman for the Chinese Foreign Ministry, accused Japan on Tuesday of "stealing" the islands.
"China will not tolerate any activity that breaks China's sovereignty or the integrity of its territory," he said at a regular news conference.
In an editorial published Thursday on its website, Global Times, a Chinese newspaper affiliated with the ruling Communist Party, said Tokyo had "chosen the wrong opponent at the wrong time and the wrong place."
"Japan inflicted the deepest atrocities on China in its modern history, which was full of humiliation," the editorial said. "If China were to pick a target country to wash out the old shame, Japan is the best choice."
The Japanese government was pressured into the acquisition by an effort to buy the islands begun in April by the outspoken governor of Tokyo, Shintaro Ishihara.
Japanese officials have sought to play down the significance of the deal and insisted that they don't want it to hurt ties with Beijing.
But animosity between the two countries over the islands runs deep.
They have come to represent what many Chinese people see as unfinished business: redressing the impact of the Japanese occupation of large swathes of eastern China during the 1930s and 1940s.
China says its claim goes back hundreds of years. Japan says it saw no trace of Chinese control of the islands in an 1885 survey, so formally recognized them as Japanese sovereign territory in 1895.
Japan then sold the islands in 1932 to descendants of the original settlers. The Japanese surrender at the end of World War II in 1945 only served to cloud the issue further.
The islands were administered by the U.S. occupation force after the war. But in 1972, Washington returned them to Japan as part of its withdrawal from Okinawa.
CNN's Jethro Mullen in Hong Kong contributed to this report.