A massive blaze ravaged two Florida mega-yachts valued at more than $20 million over the weekend in “the biggest fire loss in Fort Lauderdale history,” according to authorities and a new report.

Local fire officials responded to a report of two large yachts on fire around 4:30 a.m. Saturday at Universal Marine Center docks close to the New River in the southeastern coastal city, Fort Lauderdale Fire Rescue said in a statement.

Dramatic video posted to Facebook shows heavy smoke and fire billowing from the yachts as more than 60 firefighters and three fireboats doused it with water for five hours — preventing it from spreading to other yachts.

No one was injured.

The blaze began on a 161-foot motor yacht called Lohengrin — a custom-designed vessel valued at $12 million to $16 million built by Trinity Yachts, with crew quarters sleeping up to 10, Fort Lauderdale Battalion Chief Stephen Gollan told the Sun-Sentinel.

The crew had been aboard the vessel Friday evening but left long before the fire began, Gollan said.

The northwest wind spread the blaze to the nearby Reflections, a 107-foot Christensen yacht with four staterooms, valued at $6 million to $7 million, according to Gollan.

The yachts were docked side by side as painting and renovation work was underway.

The cause of the fire was not immediately known.

“We haven’t even begun the investigation yet,” Gollan told the Sun-Sentinel on Sunday night, as crews fought spot fires. “[Monday] morning, we plan to go in with ourselves and other resources from [the Bureau of Alcohol, Tobacco, Firearms and Explosives] and begin our investigation.”

Investigators plan to pore over video surveillance to determine whether the fire was intentionally set. If it turns out to be accidental, the exact cause might be hard to nail down because of the significant damage, Gollan told the paper.

“One of the larger concerns is how closely the yachts are docked together,” Gollan said. “Anytime boats are packed in a small area, strong winds can move flames from one to another.”

Chip McElroy, the owner of the Reflections, told the Sun-Sentinel that he had owned the vessel for 3½ years and used it to travel with his family to the Caribbean.

He called the vessel Reflections “for all the blessings in our lives.”

The yacht had spent the past two weeks at the Florida marina for its annual repainting — but now the craft is a “total loss,” according to McElroy, the CEO of McElroy Manufacturing in Tusla, Okla.

“We were a week away from being out of here,” McElroy told the paper.

He said he did not personally know the owner of the Lohengrin.