A fire burns on the amphibious assault ship USS Bonhomme Richard at Naval Base San Diego on Sunday in San Diego. Photo: AFP

Hundreds of sailors and civilian fire crews are continuing to quell the blaze on amphibious assault ship USS Bonhomme Richard for the third day in a row Tuesday at Naval Base San Diego in California as authorities said the ship is currently "stable and the structure is safe."

"For more than 48 hours, brave Sailors from commands all across San Diego have been working tirelessly alongside Federal Fire San Diego to get this fire under control," said Rear Admiral Philip Sobeck, the commander of Expeditionary Strike Group 3, in a statement.

"We have investigated the four main engineering spaces and found no major damage. There is no threat to the fuel tanks, which is well-below any active fires or heat sources," he noted.

One million gallons of fuel are reportedly stored on the Wasp-class amphibious assault ship home-ported in San Diego.

"We still have an active fire, which we are combatting from both within and outside the ship from multiple access points," Sobeck said.

Helicopters have conducted more than 1,000 helicopter water bucket drops, which is cooling the super structure and flight deck enabling fire crews to get onboard internally to fight the fire. Tugs are also providing firefighting support from the waterline, according to Sobeck.

US officials said that a total of 61 personnel, including 38 sailors and 23 civilians, have been treated for minor injuries including heat exhaustion and smoke inhalation.

Sobeck noted that US Navy will do a thorough investigation of the incident to include assessing the cause of the fire and damage to the ship. Officials said that the fire appears to have started in a vast lower cargo area.

Around 160 sailors were aboard USS Bonhomme Richard when the fire was called away at approximately 8:30 a.m. local time on Sunday. The ship is going through a maintenance availability and has a crew size of around 1,000, according to the US Navy.