Burning material was found early Wednesday at the front door of a Chiba Prefectural Government official's house in Nagareyama in the prefecture in what appeared to be an extremist attack, police said.
Hirotaka Ishizuka, 56, an administrative officer of the planning department, called police after noticing something burning in front of the door at around 3 a.m., the police said, adding that nobody was hurt.
Police suspect extremists opposed to Narita airport in the prefecture were involved in the incident due to the nature of the combustible material and burned lead wire found at the scene. Ishizuka's car, parked at the house, was also burned.
Ishizuka, who is in charge of managing airports and railroads, assumed his current post in April 2000.
No extremist activities targeting prefectural government officials have been reported since April 1998, the police said.