The Fisheries Agency on Tuesday ordered four firms to suspend catches because they allegedly paid off Russian officials to take more than their allocated quotas in the country's exclusive economic zone.

The firms, based in Wakkanai and Kushiro in Hokkaido; Hachinohe, Aomori Prefecture; and Shiogama, Miyagi Prefecture, admitted during an agency probe that they caught more than their allocated quotas from 2007 to 2009, agency officials said.

They are suspected of giving a total of ¥500 million to the Russian officials to gain approval for Alaska pollack catches exceeding their quotas under a bilateral agreement.

All of the firms except the one based in Wakkanai admitted they also caught more than their allocated quotas before 2007, the officials said.

The allegations surfaced last year during an investigation by tax authorities, who determined the four firms had concealed income and ordered them to pay about ¥200 million in back taxes, including penalties.

"We will impose a severe punishment to prevent such cases from happening again," Michihiko Kano, minister of agriculture, forestry and fisheries, said at a news conference.

Russia allowed Japan to catch 10,925 tons of Alaska pollack in its EEZ in 2010, the agency said.