Two US Navy ships were damaged in a collision about 120 miles off the Southern California coast, but no one was injured.

Two US Navy ships were damaged in a collision about 120 miles off the Southern California coast, but no one was injured, the Los Angeles Times reported Wednesday.

The amphibious assault ship Essex collided with the oiler Yukon during an underway replenishment about 9:20 a.m. No one was injured, the US Navy said in a statement.

The Essex is on its way to San Diego after 12 years as the Navy's only permanently forward-deployed amphibious assault ship. The Essex has been homeported in Sasebo, Japan.

The Yukon is a Military Sealift Command oiler ship with civilian mariners and U.S. Navy personnel.

No fuel spilled and both ships remain under their own power. The accident appears to have been caused by a steering malfunction aboard the Essex, the Navy said.

An underway replenishment is a complex and delicate operation in which a supply ship transfers fuel and other materials to a second ship while both are on the high seas. The force of the water between the two ships can sometimes pull the two vessels together. Replenishing at sea allows the Navy to continue a forward presence without returning to port.

The Essex is due in San Diego on Thursday. The Yukon is homeported in San Diego.