TOKYO: A Japanese police officer died after being found shot in a toilet near the prime minister's residence early on Friday and police were investigating a potential suicide, multiple media outlets reported.

The 25-year-old officer of the Metropolitan Police Department's riot police was found bleeding inside the toilet of a guard station early on Friday and was taken to hospital but was soon pronounced dead, public broadcaster NHK said.

Prime minister Fumio Kishida, who is currently stopping by in Singapore on his way back to Japan from an Africa tour, was not at the residence at the time.

Yusuke Takayama, an official with the Metropolitan Police Department said the police are "investigating the details" of the case, news agency Kyodo reported.