Tokyo ? Police stormed an apartment today and seized a suspected gangster who had barricaded himself in side after a deadly shooting in the streets of a Tokyo suburb in violence 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. Crime syndicates are overwhelmingly responsible for Japan’s rare gun attacks.

The events began Friday when the suspected gangster 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, identified as 36-year-old Yuji Takeshita, then barricaded himself inside his own apartment, firing a series of shots toward surrounding officers, said a Tokyo Metropolitan Police spokesman who spoke on condition of anonymity, under police protocol.

After police stormed the apartment, public broadcaster NHK showed paramedics carrying the suspect on a stretcher out of his apartment. Police said he is believed to have shot himself in the head and was taken to a nearby hospital. 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.

Though Japan has strict gun control laws, Friday’s incident was the second this week.

“The cases must be investigated inside out, and I would like (the authorities) to step up anti-crime measures,” Prime Minister Shinzo Abe told reporters later Friday. “We must make utmost effort to eradicate such shootings and gangster groups.”

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.

Analysts say the recent shootings are signs that gangsters are getting desperate in keeping their turf and finding income sources since the government stepped up anti-gang measures in the 1990s.

“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.”

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.