Naoya Kina, 22, a right-wing extremist, was arrested on the spot by police who rushed to the scene, according to a Tokyo Metropolitan Police spokesman, who spoke on condition of anonymity, citing protocol.

Kina was taken to a hospital for his cuts, which were minor, the spokesman said. The motive for the attack was unknown, he said, adding that the man was carrying a letter of protest, whose content was not available.

Right-wing extremists have committed similar attacks in the past on government buildings or embassies, including Chinese ones.

The police spokesman, however, denied that the action was related to pesticide-contaminated dumplings imported from China, which have sickened at least 10 people here and caused a nationwide panic over the safety of Chinese food imports.

The man apparently made his way into the ministry and threw a bottle filled with a flammable liquid toward the ministry's front entrance, the spokesman said, adding that other details are still under investigation. Kyodo News agency said the man climbed over a fence surrounding the ministry. -- AP