Police have launched a manhunt for a 44-year-old man in western Tokyo after he attacked high school students with a hammer and sprayed an unknown liquid at the responding officers.

According to the Tokyo Metropolitan Police Department, an emergency call came in at around 7.20am local time, with a caller reporting that “a man with a hammer is assaulting people” on a street in Fussa city.

Police say the suspect, identified as 44-year-old Teruyuki Takabayashi, attacked two students with a hammer before confronting officers at the scene and spraying them with an unidentified liquid, Kyodo News reported.

Five people were injured, with one student sustaining a serious injury to his left eye. The incident unfolded in a quiet residential neighbourhood about 700m northwest of JR Fussa station, unsettling residents during the early morning rush, local reports said.

Investigators believe the violence may have been triggered by a brief confrontation shortly before the attack. The suspect’s mother had reportedly asked a group of seven high school students gathered near their home to keep the noise down.

Although the students agreed, they did not leave the area. Soon after, Mr Takabayashi allegedly emerged with a hammer and began attacking them, The Japan Times reported.

As police arrived at the scene, the man reportedly retreated into his home and barricaded himself inside. Officers said he threatened them with what appeared to be a survival knife.

After ensuring his mother was safely removed, police say the suspect began spraying a yellow liquid at them from inside the house.

Officers eventually entered the home around four and a half hours later, but found it empty. Items resembling multiple hammers and a survival knife were recovered.

Investigators reviewed security camera footage, which showed the suspect slipping out through a back exit while officers were dealing with the liquid being sprayed from inside.

Authorities have since launched a full search operation and are treating the case as attempted murder. Police also revealed that Mr Takabayashi had previously been arrested in October 2023 on suspicion of attempted murder in a separate incident involving a teenager who was allegedly attacked with an axe.

Meanwhile, heavy police presence remains in the neighbourhood as the manhunt continues.

Japan has strict gun laws and violent crime remains rare, but there have been several high-profile knife attacks in recent years.