A U.S. cruiser equipped with an advanced missile defense system docked in Japan on Tuesday, as concerns linger over North Korea's missile program.

The USS Shiloh, a cruiser equipped with Aegis technology, which is geared toward tracking and shooting down enemy missiles, sailed into the port of Yokosuka Tuesday morning.

"Shiloh's deployment builds upon the maritime detection and tracking capability already in place in the western Pacific," said U.S. Secretary of the Navy Donald C. Winter, who was on hand for the cruiser's arrival.

Protestors could be seen among the vessels that escorted the 570 foot-long cruiser into port. One small craft carried a sign that read "Stop MD," referring to missile defense.

USS Shiloh's arrival came a day after Winter met with Japanese Foreign Minister Taro Aso. Aso hailed the cruiser's forthcoming deployment — which had been announced in April — as a buttress to the ballistic missile defense capabilities available in Japan.

The top U.S. commander in the Pacific, Adm. William Fallon, said last week that Washington and Tokyo plan to work closely to develop a joint missile shield to defend against threats posed by communist North Korea.

CountryWatch: North Korea

Those comments came in the wake of Pyongyang's test-firing in early July of seven missiles that fell harmlessly into the Sea of Japan. The tests prompted Japan to impose sanctions on the North and push for a punitive U.N. Security Council resolution.

North Korea accused Japan and the U.S. of preparing for a pre-emptive attack in the region, according to the North's official Korean Central News Agency.

"By introducing the MD with the political and military backing of the U.S., the Japanese reactionaries seek to provide a military guarantee for pre-emptive assaults on other countries and round off the capability to mount a pre-emptive attack" on North Korea, KCNA reported Tuesday, quoting the Minju Joson newspaper.

The U.S. Navy already had eight Aegis-equipped vessels in Yokosuka, southwest of Tokyo. In July, the USS Shiloh — which replaces the guided missile cruiser USS Chancellorville in Yokosuka — demonstrated its ability to shoot down missile warheads in a landmark test off Hawaii.

Japan and the U.S. also agreed earlier this year to deploy jointly produced advanced Patriot interceptor missiles on American bases in Japan for the first time.

The U.S. has about 50,000 troops in bases across Japan under a bilateral security pact.