Japan lodged a protest Monday over an unannounced port call by a U.S. nuclear-powered submarine at Okinawa.

At a press conference, Vice Foreign Minister Mitoji Yabunaka demanded measures be taken by the U.S. Navy to ensure no repeat of such an incident.

"I have been told that the U.S. side said there has been insufficient communication (within the U.S. Navy) and we have strongly demanded that measures be taken to ensure this will not happen again," said the top diplomat, adding that there is no evidence of any radioactive leakages.

The Los Angeles-class attack submarine Providence arrived at White Beach in Uruma of Okinawa Prefecture between 10:00 a.m. local time to around at noon, according to Japan's foreign ministry.

(Xinhua News Agency November 10, 2008)