LOS ANGELES (AP) _ A nuclear attack submarine used in filming ''The Hunt for Red October'' accidentally snagged a tugboat, sunk it and left one crewman missing.

The search for the night watchman aboard the tugboat Barcona was suspended and no rescue effort was planned today after the sinking 10 miles from shore.

The submarine, a San Diego-based vessel with a crew of 140, wasn't damaged and it surfaced after the accident to assist in the search for the missing sailor, the Navy said.

Brian Bellanger, who was keeping watch at the time of the accident early Wednesday, was missing Wednesday night at the end of a search by four U.S. Coast Guard vessels, two helicopters and three Navy craft, said Coast Guard Lt. Rick Button.

There was no immediate word on how the accident occurred and officials said both the tug and the sub apparently were in the correct sea lanes.

Dan Rodriguez and Mike Lynk escaped the tug and were rescued unhurt after the 6,900-ton USS Houston snagged the Barcona's tow line, said Coast Guard Petty Officer 2nd Class Elizabeth Neely.

The two scrambled onto one of two empty barges being towed by the Barcona, owned by Long Beach-based Connelly-Pacific Marine.

Bellanger's brother, Glenn, said: ''The water just caved in the boat, (which) just went straight down. Mike had the wires for the microphone, the radio, all wrapped around his neck. He said he didn't think Brian was going to make it.

''We're all hoping right now that he did, but there's 450 fathoms of water out there and that's, that's pretty deep.''

The sub was used this week in the Paramount film production ''The Hunt for Red October,'' based on the best-selling novel about a runaway Soviet sub by Tom Clancy. The film stars Sean Connery and Sam Neill. No actors were on the submarine at the time of the 4:43 a.m. accident.

A mock Soviet sub was tied near the Coast Guard headquarters on Terminal Island where Rodriguez and Lynk were brought. The accident was not related to the filming, said Navy Lt. Sonja Hedley.

The missing sailor may have gone down with the 73-foot tug, which sank southwest of Long Beach, officials said. Parsons said Rodriguez and Lynk, the surviving crew members, were asleep when the submarine struck the tow cable.

''The tug was pulled down very rapidly,'' said Cmdr. Don Parsons, who was heading the Coast Guard investigation. ''Everything happened so fast. It sank in less than a minute.

''The survivors didn't get out until the tug was already under water. The last time anyone saw the missing man was when he was seen going down to the engine room.''