TOKYO, April 17: The mayor of the Japanese city of Nagasaki, who was shot by a man police said belonged to a crime syndicate, remained in a critical condition on Tuesday and his chances of survival were slim, doctors said.

Itcho Ito, 61, seeking re-election for a fourth term in Sunday's election, was shot at least twice in the back in front of his campaign office just before 8:00 p. (1100 GMT) on Tuesday, Nagasaki police said.

Tetsuya Shiroo, 59, a senior member of a local gang affiliated with Japan's largest crime syndicate, the Yamaguchi Gumi, was arrested by police on suspicion of attempted murder. A revolver he had with him was also confiscated.

The motive for the shooting remained unclear, but public broadcaster NHK said Shiroo was upset at the city's handling of a traffic accident four years ago in which his car was damaged as it passed by a public works construction site.

After an emergency operation that lasted for hours, Ito was surviving on an artificial heart and lungs, and the likelihood of resuscitating him was “very difficult”, hospital doctors told a news conference, adding two bullets had reached his heart.

TV footage earlier showed the mayor lying face down on a sidewalk with his eyes closed as paramedics performed cardiopulmonary resuscitation after he was gunned down.

“I hope that the truth be revealed through vigilant investigation by authorities,” Kyodo news agency quoted Prime Minister Shinzo Abe as saying after news of the shooting.—Reuters