(Adds Abe comment, paragraph 8)

By Linda Sieg

TOKYO, April 18 (Reuters) - It couldn't happen here. That's what many Japanese were doubtless thinking after a gunman massacred 32 people at a U.S. university.

But the fatal shooting of the mayor of Nagasaki as he campaigned for re-election has reminded people of Japan's dark underworld of gun-toting "yakuza" gangsters, and prompted some, including Prime Minister Shinzo Abe, to call for even tighter controls.

Itcho Ito, 61, died in hospital before dawn on Wednesday just hours after being shot outside his campaign office in the southern city.

Police arrested Tetsuya Shiroo, 59, a senior member of a local gang affiliated with Japan's biggest crime syndicate, the Yamaguchi Gumi, and seized a revolver he had with him.

"This is really awful. It is related to yakuza -- ordinary people don't carry guns and don't want to carry guns," said Fumiko Tateno, 48, who works in a patent attorney's office.

"It's different from America, where the government protects people with guns," she added. "It's a very big shock."

Japan has strict gun control laws, and what firearms there are mostly in the hands of yakuza or hunters.

"Japan already has some of the tightest controls in the world," Prime Minister Shinzo Abe told reporters in response to a question about gun control. "But I think that control should be even more thorough."

Others agreed.

"Guns are banned in Japan, but even so, this sort of thing has happened. It is tragic," said Norihisa Hirano, a salesman at an IT-related firm, on his way to work on Wednesday.

"There is a black market for guns. We need better controls."

MEMBERSHIP NO CRIME

With their colourful tattoos, missing fingers and myth of a code of honour among crooks, yakuza have long been a prominent feature of Japanese society, inspiring films, novels and comics.

Membership in gangs, whose mainstays include prostitution, drugs, extortion and even finance, is itself not a crime.

Police figures show membership in mafia organisations totalled 41,500 last year -- a drop from 2005 -- but the number of hangers-on willing to do their dirty work was up at 43,200.

Gun-related crime, already minuscule, has also been on the decline in Japan, with the number of shootings falling to a record-low 53 last year. Of those, 36 were suspected of involving yakuza. Only two resulted in deaths.

That means yakuza shoot-outs grab headlines when they occur.

In February, a senior member of a group linked with the Sumiyoshi-kai, Japan's second-largest gang, was shot dead in Tokyo, sparking fears of a turf war with rival Yamaguchi Gumi.

Some Japanese said police should clamp down harder instead of treating yakuza like a necessary evil.

"The police recognise yakuza within a certain limit," said IT salesman Hirano. "But there are laws, and they should be rooted out."

Japanese politicians have been targeted in the past by gangsters and right-wing groups, whose membership often overlaps. Some attacks followed remarks that offended the groups' nationalist sentiments, while others were attributed to fallouts over murky dealings.

Ito's predecessor was shot and seriously wounded in 1990 by a member of a far-right group after suggesting the late Emperor Hirohito should be held responsible for World War Two.

Friendlier links between politicians and gangsters also have a tradition in Japan. "Before World War Two and after, there have been ties between gangsters and politicians," said Manabu Miyazaki, a writer on organised crime whose father was a gangster.

"It's a kind of give and take." (Additional reporting by Chisa Fujioka and Elaine Lies)

AlertNet news is provided by