The Maritime Self-Defense Force destroyer Shirane was slated to be sent to support U.S.-led antiterrorism operations last November but the mission was scrubbed at the last minute when an anonymous letter was received warning of repair irregularities, leading the government to deploy an Aegis warship instead, sources said.

The 5,200-ton Shirane, operating out of the MSDF's Yokosuka base in Kanagawa Prefecture, was to sail to the Indian Ocean as part of Japan's support for the U.S.-led effort.

The sources said that the letter is believed to have been sent by an MSDF member who opposed the Shirane's dispatch. The sender remains unknown.