Twenty-three other crew on the USS San Francisco were being treated "for a range of injuries including broken bones, lacerations, bruises and a back injury," following the accident on Friday, Petty Officer Alyssa Batarla told

The accident occurred when the vessel was conducting underwater operations 560 kilometers (350 miles) south of its base at Guam, the Navy said.

The submarine was due to arrive back in port on Monday. An investigation into the accident has already started, officials said.

The navy said the submarine's nuclear plant had not been damaged and its hull was still intact.

The submarine was heading back to base under its own steam, but on the surface.

The grounding occurred as the Los Angeles class submarine with its crew of 137 was heading for a port visit in Brisbane, Australia.

"There were no reports of damage to the reactor plant, which is operating normally," the US Navy said in a statement Saturday. Officials said the hull of the vessel was intact.

Los Angeles class submarines are 110 meters (360 feet) long and have one nuclear reactor and one shaft, according to US Navy data.

Submarines of that class are able to get on station quickly, stay for an extended period of time and carry out a variety of missions including deployment of special forces, minelaying, and precision land attacks.

The USS San Francisco is one of three submarines of its class to be based in Guam. It has been there since 2002. It can carry out intelligence gathering and take special forces on missions. Its strike arms usually include Tomahawk missiles.

The incident occurred at 12:00 noon Guam time (0200 GMT Saturday), the Navy said.

In 2001, another submarine, the USS Greeneville, collided with a Japanese fishing boat off Hawaii, killing nine Japanese boys and men.

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