TOKYO — Japan and the United States, facing North Korea's apparent plans to test-launch a ballistics missile, have agreed to deploy advanced Patriot interceptor missiles on American bases in Japan for the first time, officials said today.

The U.S. plans to deploy the Patriot Advanced Capability-3 missiles — designed to intercept ballistic missiles, cruise missiles or aircraft — as soon as possible, a Japanese Defense Agency spokeswoman.

The spokeswoman, who spoke on condition of anonymity in line with agency policy, said the sites and exact timing for the deployment have not yet been decided.

The plan was first reported today in Japan's largest newspaper Yomiuri Shimbun. It said the U.S. military would deploy three or four batteries of the surface-to-air missiles on the southern island of Okinawa by the end of the year and send 500-600 additional U.S. troops there.

Up to 16 missiles can fit in a single PAC-3 battery, according to the system's manufacturer, Lockheed Martin Corp.

The plan was proposed by U.S. officials during a June 17 meeting in Hawaii, the newspaper said.

Japan and the U.S. signed an agreement in 2005 allowing Japan to produce PAC-3 missiles for deployment during fiscal 2006 at Japanese bases. But the deployment plans for Okinawa are apparently separate from that deal.

Recent intelligence reports indicate North Korea may be preparing to test-fire a Taepodong-2, an advanced missile believed capable of reaching parts of the U.S.

The United States, Japan and other countries have urged North Korea to halt any plans to test the missile, while Pyongyang has insisted it has the right to do so if it chooses.