Kauai - An explosion that has yet to be explained was heard and felt in Lihu'e Sunday night between 8:30 and 9:30, according to witnesses.

County Public Information Officer Mary Daubert said a police officer did check out the area in response to calls but was not able to determine the cause.

Police Commissioner Tom Iannucci, who was waiting with his kids at the Lihu'e Taco Bell drive-through, said there was no mistaking the noise and "slight concussion" to the car, which he likened to a dynamite explosion.

"Being a former Marine who served in a war zone, Beirut, I know exactly what it was," Iannucci said.

Iannucci called 911 to report the blast and was told by the dispatch operator that there had been other calls about an explosion in the area.

"It was too large to be something simple," he noted, adding that he did not see anything, smoke or otherwise. "To ... hear it as loud as I heard it and feel the slight jolt in the vehicle, something happened."

Don Uohara was relaying cables with a Wasa Electrical Services crew at the stop light at Kaumuali'i Highway and Nawiliwili Road when he, too, heard a "pretty loud" boom.

"We turned around and said, 'What was that?'" Uohara said of his and coworkers' reactions.

Kauai Film Commissioner Art Umezu said he did not know of any pyrotechnics that took place in the area for the film Tropic Thunder, which is being produced on-island. The movie follows actors shooting a war flick who become their characters after a strange series of events.

"They don't believe they've done anything, especially on a Sunday," Umezu said after talking to the film's production office.

According to Capt. David Bukoski of the Fire Prevention Bureau, there have been explosions and testing in the past for the film, but nothing was scheduled or permitted for Sunday.

Bukowski said the Fire Department has a good relationship with the certified and licensed pyrotechnicians.

"They are very cognizant of the public," Bukoski said of the crew.