Story highlights When the search ends late Tuesday, an area the size of Florida will have been searched

Surfers and those along the coast are warned about possible debris

(CNN) The U.S. Coast Guard will stop actively searching for the 12 Marines who went missing when the two helicopters carrying them apparently crashed off the coast of Hawaii last week. The search suspension goes into effect at sunset Tuesday.

No survivors have been found nor bodies reported recovered.

"A decision to suspend searching without finding survivors is extremely difficult given the depth of its impact. ... Our thoughts and prayers are with Marine Corps helicopter squadron and particularly with families and loved ones of those missing," said Coast Guard Capt. Jim Jenkins in a written statement.

A witness last Thursday saw a fireball in midair; another reported seeing a flare. The U.S. Marine Corps notified the the Coast Guard that two CH-53 copters, carrying six men each, were missing. A search ensued involving the Navy, the National Guard, as well as Hawaii fire, police and Ocean Safety.

When the search is officially suspended at sunset Tuesday in Hawaii, a total of 130 rescue personnel will have covered 40,530 nautical square miles, an area about the size of Florida, in a 115-hour search effort, the Coast Guard said.

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