Tokyo and Air Self-Defense Force police arrested a former ASDF member Friday for allegedly leaking classified early-warning aircraft performance data provided to Japan by the US government.

So Kanno, 58, the former ASDF colonel and now an employee at a defense equipment trading firm, denied that he violated a secret protection law incidental to the Japan-US mutual defense assistance agreement, the Metropolitan Police Department's Public Safety Bureau said.

The MPD bureau and the Air Police Group suspect that Kanno showed information including data on the performance of the E-2D, the new-type early warning aircraft, on a personal computer display to another defense equipment trader's employees and gave them a memory stick containing the information.

Since the law took effect in 1954, performance data and other information on defense equipment, such as aircraft, vehicles and weapons, have been classified as special secrets.

According to the Tokyo police, Kanno was a section chief at the ASDF's Air Development and Test Command responsible for deploying troops and managing them at the time of the incident.

He and the trading firm officials had known each other.

Investigative sources said the company officials probably did not know the data were defense secrets.

The leak came to light after a rival US company of the E-2D maker received the data from the Japanese trading firm six months later and reported to the US government that they could be classified ones, the sources said.

At a press conference the same day, Chief Cabinet Secretary Yoshihide Suga said it is "extremely regrettable" that classified defense equipment data were leaked.

The incident "is feared to undermine public trust in the Defense Ministry and the SDF and shake the relationship of trust between Japan and the United States," he went on to say.

In past cases of violation of the same law, a senior Russian trade official stationed in Japan abetted in 2002 a defense equipment sales firm president who had been an ASDF member in obtaining and offering data on US-made missiles mounted on fighter jets, and data on the Aegis missile defense system changed hands within the Maritime SDF in 2007 after they were obtained by an MSDF member.

JIJI Press