Japan's navy held its annual fleet review on Sunday, with destroyers lining the seas and missiles roaring through the air in a major display of this country's military power. More than 8,100 troops and 48 ships _ including Aegis-equipped destroyers and state-of-the-art submarines _ took part in the review, which was held in waters just south of Tokyo. «Our country's Self-Defense Forces are being called upon to play a more crucial and varied role,» Prime Minister Shinzo Abe said in an address to the sailors aboard the Kurama, a destroyer that served as flagship during the maneuvers. Abe singled out North Korea as a major threat to Japan, saying its recent ballistic missile test launches and its claim to have exploded a nuclear device on Oct. 9 are «grave and unforgivable.» Though planned well before North Korea's nuclear test, Sunday's review put the Japanese navy's best ships on display, from vessels rigged with the advanced Aegis radar system to new, conventionally powered submarines and high-speed hovercraft capable of quickly putting heavy vehicles or hundreds of troops ashore in difficult-to-reach locations, the Associated Press reported. «I believe this is an excellent opportunity to demonstrate our readiness,» Abe, who assumed office last month, said in his address.