The guided-missile destroyer USS John S. McCain and the guided-missile cruiser USS Shiloh have joined the USS Benfold and the USS Fitzgerald, both guided-missile destroyers, to monitor the launch, a Navy official said Saturday.

North Korea announced earlier this month that it will launch a “satellite” sometime between Monday and Dec. 22 to commemorate the first anniversary of the death of former leader Kim Jung-il, who died Dec. 17.

The upcoming launch is the secretive communist nation’s second attempt in eight months. A launch in April ended when the rocket broke apart over the Pacific.

Western nations have said what North Korea claims are satellite launches are actually ballistic missile tests, since the same technology applies. The U.N. has banned North Korea from conducting such tests.