Japan issued certificates for fish exports to the European Union after it said only products that don't exceed radiation limits or are from areas unaffected by the Fukushima No. 1 nuclear accident would be allowed, the Fisheries Agency said.

Food produced in 12 prefectures closest to the Fukushima plant are required by the EU to be tested for radiation, according to the European Commission. Certificates of origin are required for products from other prefectures.

"So far we have issued documents to certify fish origins, as there were no exports of seafood from the 12 Japanese prefectures to Europe," Miho Wazawa at the trade office of the Fisheries Agency said Thursday in a phone interview.

Russia's food-safety watchdog restricted supplies of fish and marine products from 242 processors in Japan, joining the U.S. and EU in limiting shipments. India suspended Japanese food imports for three months or until "credible information" on the radiation hazard is available, its Health Ministry said Tuesday. Sushi restaurants and hotels, including Shangri-La, Asia's luxury chain, dropped Japanese seafood from their menus because of radiation fears.

Japan exported 565,295 metric tons of marine products worth ¥195 billion last year. Hokkaido and the prefectures of Kagoshima and Nagasaki are major shippers of Japanese seafood to overseas markets, said Rika Tatsuki, a spokeswoman for the National Federation of Fisheries Cooperative Associations in Tokyo.

"Sales of fish from these prefectures are also declining as the nuclear plant accident and dumping of radioactive water from the facility stoked concerns about safety and spurred excessive reactions from consumers," she said Thursday.

Tokyo Electric Power Co. dumped radioactive water into the sea for a fourth straight day, contaminating the ocean and drawing anger from Japanese fishermen and countries including South Korea and Russia.

Russia imported about 59,000 tons of fish from Japan last year, consisting mostly of saury, according to Alexander Savelyev, spokesman for Russia's Federal Agency on Fisheries.

Japan detected higher-than-acceptable levels of cesium Tuesday in samples from sand lance caught off Ibaraki Prefecture, south of Fukushima, where the plant is leaking radiation. It was the first discovery of tainted seafood in the country since the March 11 earthquake and tsunami damaged the nuclear plant, slashing demand for fish caught in the region and spurring fishermen to halt operations.