WASHINGTON: Japanese Defense Minister Fumio Kyuma has asked U.S. Defense Secretary Robert Gates for more information about the F-22 fighter jet built by Lockheed Martin Corp., a senior Japanese official said on Tuesday. U.S. law currently bans any exports of the F-22 Raptor, but some lawmakers and defense officials say there is growing interest in making it possible to export a modified version of the advanced fighter to close allies such as Japan. "If we make the F-22 a candidate, we need full information on this air fighter," said the official, who asked not to be named. Japanese military officials are eyeing the supersonic F-22, the U.S. Air Force's main air superiority fighter, as part of their response to growing regional missile threats. The Japanese official said Kyuma discussed the F-22 with Gates during their meeting on Monday, saying Japan would need more data on the fighter jet's specifications so it could be formally considered in an upcoming competition. Kyuma asked Gates "to provide us with more information so that we may proceed," the official said. Japan is aware of U.S. congressional concerns about protecting the F-22's classified technologies, he added. But resistance to exports appears to be weakening, according to U.S. congressional officials and analysts. The House of Representatives last year voted to remove the export ban on the F-22, which is attached to the annual defense appropriations legislation, but the measure was reinserted during conference negotiations with the Senate. The issue is important to Lockheed and its F-22 partners -- Boeing Co. and United Technologies Corp.'s Pratt & Whitney unit -- because overseas sales could extend the production line beyond 2011, when the last of the 183 Raptors currently planned is due to be sent to the U.S. Air Force. One senior U.S. defense official told Reuters on Tuesday that there was a growing feeling "that this be the right time to look at it," although he cautioned that there were no concrete plans to move ahead at this point. Advocates for foreign sales had not yet reached "a critical mass," said the official, who asked not to be named. Air Force Lt. Gen. Jeffrey Kohler, who heads the Pentagon's Defense Security Cooperation Agency, also warned last week that designing an export version of the F-22 could cost more than $1 billion and be "prohibitively expensive" for any would-be foreign buyer. The aircraft, which entered the U.S. combat fleet in December 2005 after 20 years of development, currently costs $136 million per copy, not including development costs. The first F-22 overseas deployment was to Kadena Air Base on Okinawa, Japan, this year. Twelve are still in the region. Loren Thompson, a defense analyst close to the Pentagon and to military contractors, said the F-22's ability to fly at supersonic speeds meant it was uniquely suited to chasing down cruise missiles that could be directed at Japan. The F-22 would be an integral part of any future missile defense architecture involving Japan, said Thompson, of the Virginia-based Lexington Institute. Israel is also widely reported to have shown interest in acquiring the F-22.