The head of a Japanese company suspected of illegally exporting instruments that could be used in the production of nuclear weapons has defended his company's actions.

Japan's Mitsutoyo Corporation is insisting it did nothing wrong by selling high-precision calibrating equipment, along with its operating software, to companies in China and Thailand.

Japanese media quote police investigators as saying that at the same time the machines were sent to China and Thailand in 2001, such instruments were being shipped to Libya via the Gulf state of Dubai.

Media reports say serial numbers on the equipment in Libya matched that on machines sold by a Mitsutoyo subsidiary to a Malaysian company regarded as a black market conduit for nuclear weapons components. One newspaper (Sankei Shimbun) quotes police sources as saying they fear that some of the equipment also made its way to North Korea.

Company president Kazusaku Tezuka met reporters on Tuesday, a day after police raided ten company locations, including its factory. Tezuka says he does not believe his company did anything illegal.

Japan's Foreign Exchange and Foreign Trade Law forbids the export of precision equipment that can be converted for military use, unless permission has been granted.

Experts say the equipment Mitsutoyo exported could be used for uranium enrichment, a technology that can produce fuel for peacetime nuclear reactors, but is also essential for producing atomic bombs.

Japanese media reports say the International Atomic Energy Agency, the United Nations' nuclear watchdog, discovered the Mitsutoyo equipment during inspections in late 2003 and early 2004 of Libya's now-abandoned nuclear weapons program.

Mitsutoyo is a 72-year-old company headquartered in Kawasaki, just south of Tokyo.

The investigation of the company comes a month after Japan's trade ministry announced it was investigating

Yamaha Motor for sales to China of small helicopters that could be converted to military use.