The Fisheries Agency began questioning on Tuesday the presidents of four fishing companies over allegations they bribed Russian government officials so they could catch more than their allocated quotas in Russia's exclusive economic zone, officials said.

The firms are suspected of giving a total of ¥500 million to the Russians over three years to 2009 to gain tacit approval for walleye pollack catches exceeding the designated quotas under a bilateral agreement. If the allegations are true, the firms violated the fisheries law and could face severe penalties, including having their licenses revoked, the officials said.

The presidents were being questioned by ministry officials on a voluntary basis. Allegations have also emerged that other fisheries firms have been providing money to Russian authorities in connection with salmon and saury catches, which the agency plans to take up at the beginning of next year, government sources said.