Japanese Emperor Akihito, who has spent much of his time on the throne trying to heal the wounds of World War Two, intends to abdicate in a few years, public broadcaster NHK and other domestic media said on Wednesday, a step that would be unprecedented in modern Japan.
The 82-year-old monarch, who has had heart surgery and been treated for prostate cancer in recent years, expressed his intention to the Imperial Household Agency, NHK said.
It did not cite a reason and officials at the agency could not immediately be reached for comment.
Kyodo news agency, quoting a government source, said Akihito had been expressing his intention to abdicate to people around him for about a year, although in a separate report Kyodo quoted a senior Imperial Household Agency official as denying that the reports were correct.
Akihito has been cutting back on his official duties, handing over some of the burden to his heir, Crown Prince Naruhito, 56.
Born in 1933, Akihito was heir to Emperor Hirohito, in whose name Japan fought World War Two.
The soft-spoken Akihito marked the 70th anniversary of World War Two's end last year with an expression of "deep remorse", a departure from his previous remarks seen by some as an effort to cement a legacy of pacifism under threat from conservative Japanese nationalists.
"Looking back at the past, together with deep remorse over the war, I pray that this tragedy of war will not be repeated and together with the people express my deep condolences for those who fell in battle and in the ravages of war," he said.