Former defense chief Keisuke Nakanishi suffered a slight leg injury after being assaulted by an unknown assailant at Tokyo's Haneda airport late Jan. 3, police said.Nakanishi, who served as director general of the Defense Agency in 1993, was slightly injured on the left leg after an unidentified man attacked him with what appeared to be an iron pipe just as Nakanishi was boarding an elevator to a VIP waiting room for All Nippon Airways, according to police. The man then ran to a car waiting for him outside, which sped away with another man at the wheel, police said.Nakanishi, a member of the largest opposition party, Shinshinto, resigned as a House of Representatives member in May 1995 to take moral responsibility for the arrest of his son for marijuana possession. He was re-elected last October.