A National Police Agency poll of 2,956 local-government departments that deal directly with the public found that about 30 percent of them have had confrontations with gangsters, and around 70 percent of those faced extortionist demands in the past year alone.

The NPA, presenting the data to the National Public Safety Commission, vowed to crack down on attempts by the yakuza and other underworld elements to intimidate local authorities.

Most mobsters who showed up at local government offices used abusive language, and some vandalized government property or threatened physical violence, the NPA said.

The agency sent questionnaires to all 47 prefectural governments and some 700 municipal governments in January to determine the extent of the problem at five local-government departments that typically have direct dealings with the public -- those in charge of general affairs, public works, the environment, welfare and real estate. Townships and villages were not covered in the study.

The survey, which lasted through February, found that 903, or 30.5 percent, of the 2,956 departments responding said they have experienced "improper" demands from gangsters. Of them, 666 departments said they had to deal with gangsters during the past year.

Some officials said they were pressured to make purchases from mobsters. Others were asked to subscribe to newsletters published by organizations with underworld links.

While 80.3 percent of local officials who dealt with gangsters said they rejected their demands, 17.8 percent heeded them in one form or another, the NPA said.