(KHNL) - A scary Sunday for some residents in Leeward Oahu as they witness a mysterious explosion at sea.
Fire and Coast Guard crews search by land, air and sea, trying to figure out what it was.
"Something splash with black smoke," said Jeff Lono, witness.
"It was a really, really tall splash," said another witness.
People who saw the event describe it as a blast about a couple miles away from Ewa Beach.
"I had no idea. I thought we were getting attacked at first," said Josh Shin, witness.
After combing the area for 90 minutes, rescue crews called off the search.
"We didn't find any evidence of a crash of any kind or other activity that would've indicated an an emergency," said Capt. Terry Seelig with the Honolulu Fire Dept.
But numerous witnesses describe the same scene. Lono even used his binoculars to get a closer look.
"Just a couple of military boats out there," said Lono.
"I was thinking the Navy was out there doing something," said another witness.
They're right. Navy officials confirm the loud explosion was part of RIM-PAC, which continues this week. Officials say the area off Iriquois Point is designated for military training. They also say they obtained the proper permits and notified nearby vessels.