Crimes by rightist groups went up 40 percent during the first eight months of this year from the same period last year, the National Police Agency said Thursday.

Police across the country acted against 171 criminal cases, including rightists' efforts to obstruct auctions aimed at retrieving failed loans, it said. The NPA said rightist groups have been increasingly involved in crimes related to the underworld and "sokaiya" corporate extortionists amid the widespread payoff scandals involving brokerages and other major businesses.

If the number of crimes by rightists continues growing at this pace, it will surpass 250 cases annually for the first time in five years, the NPA said. The NPA has directed prefectural police across the country to intensify efforts to crack down on illegal activities by these groups.