Actor Rob Lowe mourns victims of California boat fire, says he's been on board 'many times'

Dozens are missing after a fire on the Truth Aquatics dive boat, "Conception" near Santa Cruz island in Southern California's Channel Islands on Monday, Sept. 2, 2019. Dozens are missing after a fire on the Truth Aquatics dive boat, "Conception" near Santa Cruz island in Southern California's Channel Islands on Monday, Sept. 2, 2019. Photo: Ventura County Fire Department Photo: Ventura County Fire Department Image 1 of / 34 Caption Close Actor Rob Lowe mourns victims of California boat fire, says he's been on board 'many times' 1 / 34 Back to Gallery

"West Wing" and "Parks and Recreation" actor Rob Lowe took to Twitter to mourn victims of the Conception, a dive boat that caught fire in California's Channel Islands early Monday morning.

"My heart breaks for those onboard the Conception," the actor tweeted. "An unspeakable horror on a boat I've been on many times. My prayers and thoughts are with the families."

The Conception was on a weekend scuba diving excursion that featured a visit the Northern Channel Islands. 34 people are presumed to have died in the fire.

My heart breaks for those onboard the Conception. An unspeakable horror on a boat I’ve been on many times. My prayers and thoughts are with the families. — Rob Lowe (@RobLowe) September 2, 2019

The boat, owned by Santa Barbara company Truth Aquatics, was chartered by Santa Cruz company Worldwide Diving Adventures.

READ MORE: What we know about the Santa Cruz Island boat fire disaster

"On the Labor Day trip, divers have the unique opportunity to explore the pinnacles of San Miguel Island," an advertisement for the trip from Worldwide Diving Adventures reads. "The beginning of September is the best time to be at San Mig, which see strong winds and swell during much of the year."

The boat was anchored in Platt's Harbor off Santa Cruz Island when a fire broke out at 3:30 a.m., with passengers sleeping below deck.

25 bodies have been recovered, and nine individuals have not been accounted for.

Eric Ting is an SFGATE staff writer. Email: eric.ting@sfgate.com | Twitter:@_ericting