Japanese trade officials have placed trade restrictions on Sony's PlayStation 2 because of concerns that the gaming system could be used for a military processor. The fear is due to PlayStation 2's high-speed graphic processing. Theoretically, the processor could be removed from the console and used in missile guidance systems. For example, a missile like a Tomahawk needs to locate its destination as it flies through the air and use high-speed graphic processing to pinpoint its target. After the announcement, on Monday, April 17, of the restrictions, Sony's stock plunged 9% on the Tokyo Stock Exchange. The company was aware of the product's restriction since its March debut in Japan. This official announcement comes on the heels of Sony Corp.'s plans to equip the Fall U.S. release of the PlayStation 2 with a hard-disk drive and modem. Currently, Sony is discussing the size and details of the disk drive and modem with various computer and tech companies. The additions will be finalized and announced at E3. The new add-on is a probable stab back at Microsoft, which will include a hard-disk drive in its X-Box gaming console, to be released in 2001. Commenting on how the restrictions may effect the U.S. release, a Sony spokesman said, "This is the first time that a dedicated entertainment product has been placed under export restriction but we do not foresee any problem with our planned exports to the United States and Europe." The PlayStation 2 has been hampered with problems since its release, the first of which was a reported problem with its DVD playing system. Nonetheless, the gaming system has already sold 1.4 million units in Japan.