Police have arrested a 47-year-old man who took part in a regularly held anti-Korean demonstration in Shinjuku Ward, Tokyo, for allegedly assaulting another man protesting the rally.

The man arrested Monday identified himself as Hiroshi Akai, an unemployed former Self-Defense Force member from Kumagaya, Saitama Prefecture. Akai said he had "accidentally bumped into" the other man, according to the Metropolitan Police Department.

Police allege Akai hurled himself at the 51-year-old company employee Sunday evening after the protest in Shinjuku. He was held by riot police who were guarding the demonstration.

Rightwing groups, including one claiming to be "citizens who do not condone privileges given to Koreans in Japan," have been staging demonstrations several times a month in Shinjuku and nearby Shin-Okubo, home to a large ethnic Korean population.