A rightwing extremist was sentenced Thursday to a 4 1/2-year prison term for taking a woman hostage at NHK's Kyoto bureau in January.

Ko Yamamoto, 45, a senior member of the rightist group Nippon Minzoku Giyugun and a native of Mie Prefecture, was found guilty by the Kyoto District Court of forcing his way into the bureau carrying a knife and a plastic bottle of kerosene on Jan. 18 and holding the NHK employee hostage for 4 1/2 hours.

Yamamoto barricaded himself in the first-floor lobby and demanded that the station air his message criticizing the government's response after last year's Sept. 11 terrorist attacks in the United States.

Prosecutors emphasized the posttraumatic stress disorder the woman suffers over the incident. They demanded a six-year prison term.

Presiding Judge Hiroshi Furukawa said Yamamoto's crime, targeting a mass media organization, had a serious social impact and caused the hostage to suffer psychological damage.

"He bears a grave criminal responsibility, given his self-righteous motive of trying to publicize his rightist thoughts," Furukawa said.