A grey whale calf emerges from the water at the San Ignacio Lagoon in Mexico in 2010. Volunteers and Navy personnel returned a 12-tonne whale to the sea after it became stranded on a beach in the southwestern Mexican city of Oaxaca, officials said Saturday.

Volunteers and Navy personnel returned a 12-tonne whale to the sea after it became stranded on a beach in the southwestern Mexican city of Oaxaca, officials said Saturday.

About 150 worked with over 40 Marines for 12 hours Friday on the Pacific Coast beach to keep the whale alive and maneuver it back into the water.

Local military commanders ordered marine officers, underwater specialists and other Navy personnel "to help the whale return to the sea," the Navy said in a statement.

The marines used two patrol boats, a smaller boat and vehicles to move the whale off the beach and back into the ocean.

The nine-meter (30-foot) whale suffered injuries to its right flipper, apparently from lying on its side on the beach, the statement said.