TOKYO - The Chinese embassy in Tokyo has received a bullet in the post, with the sender giving their name as the Japanese prime minister, police and reports said Friday, amid a festering territorial row.

An envelope containing the rifle bullet arrived at the embassy on Thursday morning, Jiji Press said. A spokeswoman at the prime minister’s office said only that the premier had not sent the bullet, without elaborating on any action it might take. Noting that the sender’s name written on the envelope was “Yoshihiko Noda”, embassy officials took it to police, Jiji said, citing investigative sources. There was no letter included.

“It is true that an envelope containing a bullet-like object was sent to the embassy,” said a police spokesman. “Police are investigating whether it was a real bullet.” Tensions between Japan and China have flared since the nationalist governor of Tokyo said he wanted to buy the Senkaku Islands.