The mayor of the Japanese city of Nagasaki was shot to death in a brazen attack Tuesday by an organized crime chief apparently enraged that the city refused to compensate him after his car was damaged at a public works construction site, police said.

The shooting was rare in a country where handguns are strictly banned and only five politicians are known to have been killed since World War II.

Mayor Iccho Ito, 61, was shot twice in the back at point-blank range outside a train station Tuesday evening, Nagasaki police official Rumi Tsujimoto said.

One of the bullets struck the mayor's heart and he went into cardiac arrest, according to Nagasaki University Hospital spokesman Kenzo Kusano. Ito died after emergency surgery, said Nagasaki prefectural police official Hirofumi Ito.

Tetsuya Shiroo, a senior member of Yamaguchi-gumi, Japan's largest organized crime syndicate, was wrestled to the ground by officers after the attack and arrested, police said.

He later admitted to shooting Ito with a handgun with the intent to kill, Nagasaki chief investigator Kazuki Umebayashi said at a news conference.

Prime Minister Shinzo Abe called for a "rigorous investigation."

"This murder, which took place in the middle of an election campaign, is a threat to democracy," Abe said early Wednesday. "We must eradicate violence firmly."

It was the second attack in the last 20 years against a mayor of Nagasaki, which was destroyed by a U.S. atomic bomb in the closing days of World War II in 1945 and whose leaders have actively campaigned against militarism.

In 1990, Mayor Hitoshi Motoshima was shot and seriously wounded after saying that Japan's emperor, beloved by rightists, bore some responsibility for World War II.

Tuesday's attack appeared to involve a more trivial matter, however.

Shiroo reportedly clashed with Nagasaki city officials in 2003 after his car was damaged when he drove into a hole at a public works site. He tried unsuccessfully to get compensation from the city after his insurance company refused to pay up, according to Japanese broadcaster NHK.

Shiroo also sent a letter to broadcaster TV Asahi to protest recent money scandals linked to Ito, including hidden accounts and public works contracts, Kyodo reported.

Backed by the ruling Liberal Democratic Party, Ito was campaigning for his fourth term in office before Sunday's elections. He was an active figure in the movement against nuclear proliferation, heading a coalition of Japanese cities calling for the elimination of nuclear weapons.

"Mayor Ito had a strong and boundless passion for peace," said Sunao Tsuboi, leader of a survivors' group based in Hiroshima, a city also flattened by a U.S. atomic bomb in 1945.

Commonly known as yakuza, Japan's organized crime groups are typically involved in real estate and construction kickback schemes, extortion, gambling, the sex industry, gunrunning and drug trafficking.

The yakuza also have had a long-standing political alliance with right-wing nationalists in Japan, although authorities did not indicate that Tuesday's attack was politically motivated.

Organized crime groups are behind most shootings in Japan, with two-thirds of the country's 53 known shootings last year being gang-related, according to the National Police Agency. Police estimate there are about 84,500 gangsters across Japan.

Shinichi Tada, a 44-year-old manufacturing company worker at a train station in Tokyo, said he felt gun use was increasing among gangsters and wanted laws tightened.

"I want Japanese laws to protect the general public," he said while reading an extra on the mayor's death. "I do not want Japan to be like the U.S."

Chief Cabinet Secretary Yasuhisa Shiozaki said Wednesday that the government would strengthen cooperation among law enforcement agencies to stop gangsters from getting their hands on guns.

Attacks on politicians in postwar Japan are extremely rare.

In 1960, Socialist leader Inejiro Asanuma was killed in an attack by a sword-wielding 17-year-old that riveted the nation.

In 2002, a ruling party politician was fatally stabbed in a dispute over political funds. In the 1990s, a Liberal Democrat lawmaker was killed at his home by his daughter and an opposition lawmaker was stabbed to death by a mental patient.

Last year, a right-wing extremist burned down the house of ruling party lawmaker Koichi Kato after the politician criticized then-Prime Minister Junichiro Koizumi's pilgrimage to a controversial Tokyo war shrine. No one was home at the time.

Ito was born in Nagasaki on Aug. 23, 1945, just two weeks after the atomic bomb devastated the coastal city on Japan's southernmost main island of Kyushu.

He is survived by his wife and two daughters, according to a Nagasaki city official who spoke on condition of anonymity, citing protocol.