Police stormed an apartment early today and seized a suspected gangster who had barricaded himself inside after a deadly shooting in the...

TOKYO — Police stormed an apartment early today and seized a suspected gangster who had barricaded himself inside after a deadly shooting in the streets of a Tokyo suburb in violence that officials said may signal infighting in the Japanese underworld.

The violence came days after the mayor of Nagasaki was gunned down by a reputed mobster in an unrelated killing.

On Friday, the suspected gangster, identified as 36-year-old Yuji Takeshita, fatally shot another mobster from the same group on the street in a western suburb of the capital, said local police official Yukio Tonose.

The shooter then barricaded himself inside his own apartment, firing shots toward surrounding officers before police stormed the apartment, said a Tokyo Metropolitan Police spokesman. Television later showed the suspect being carried out on a stretcher.

Police said he is believed to have shot himself in the head. Kyodo News agency said he was seriously wounded.

Investigators later found a pair of handguns in his apartment and arrested the suspect at the hospital for allegedly violating the gun-control law, Tokyo police said. Handguns are strictly banned in Japan, and only police officers and others — such as shooting instructors — with job-related reasons can own them. Hunting rifles are also strictly licensed and regulated. Crime syndicates have smuggled foreign guns into Japan.

On Tuesday, a gangster who unsuccessfully sought compensation from the city for damage to his car fatally shot the mayor of Nagasaki. Police arrested Tetsuya Shiroo, a senior member of Japan’s largest crime syndicate, the Yamaguchi-gumi, and said he admitted to the attack.

“Gangsters used to keep their guns to themselves, largely to protect their turf,” former National Police Agency official Yutaka Takehana told public broadcaster NHK. “The recent cases indicate gang groups are getting desperate for money.”

The boss of a gang affiliated with the Tokyo-based Sumiyoshi-kai syndicate was shot to death in February, and the killing was thought to have prompted at least three more shootings at gangland headquarters in Tokyo.