The Japanese government plans is to extend its anti-piracy mission off Somalia for another year.  The Japanese Defense Ministry said that incidents involving pirates are still occurring frequently in waters off the African nation. It said if Japan suspends the mission, pirates could become much more active, Japan\'s (NHK World) website reported.  The Maritime Self-Defense Force has been escorting Japanese and foreign vessels off Somalia for three years. The current mission will expire on July 23.  The Defense Ministry will continue deploying two destroyers and two patrol planes and will send more security personnel to the mission\'s base in Djibouti.  The ministry will also open a liaison office in Djibouti to coordinate activities with other countries.  The Cabinet is expected to approve the extension on Friday at the earliest.