The Coast Guard warned Saturday evening of a potential terrorist threat to "maritime interests" around Puget Sound.
"Based on information received across the U.S. Government, there is a credible threat to maritime interests from swimmers and divers," Lt. Scott Casad of the Coast Guard Marine Safety Office Puget Sound said in a release.
He said the Coast Guard had told local port officials and maritime business owners to be on guard for suspicious activity.
No further details on possible targets or what triggered the warning were released. Casad did not immediately return a phone call Saturday evening.
The warning followed one from FBI national headquarters on May 23 that "various terrorist elements have sought to develop an offensive scuba diver capability."
FBI agents have been questioning scuba diving instructors in Washington and around the country about any suspicious activity, including students interested in learning about underwater demolition.
Also, the Washington State Patrol last week was making random vehicle searches at public ferry terminals. The searches were done on the advice of the Washington State Ferries Security Committee, made up of staff from the Coast Guard, State Patrol and ferry system.
The Coast Guard's Casad asked Saturday that any suspicious maritime activity be reported to the Coast Guard Marine Safety Office Puget Sound, at (206) 217-6230 or 1 (800) 688-6664.