An explosion occurred at Kyushu University in the city of Fukuoka Friday morning and an unidentified human body was found in the debris, local police said.

The cause of the 6:40 a.m. blast on the university's campus remains unknown. A janitor made an emergency call after hearing it and seeing smoke coming out of the first floor of a three-story building.

The fire was quelled about two hours and 45 minutes later. A body, the gender and age of which were hard to determine because of severe damage, was found in an office on the first floor, according to the Fukuoka Prefectural Police.

The police are investigating the cause of the blast and trying to identity the body. A man in his 40s who had been using the office has become unreachable since the blast, investigative sources said.

The building where the blast occurred belongs to the Law Department, according to the Kyushu University. The school is on summer break and there are no lectures.

The university has been making preparations to move to a new campus in Nishi Ward. The Law Department is also scheduled to move by late September and start the new semester around October.