The United States Navy has announced the formation of an international force to provide security in the dangerous shipping lanes in the Gulf of Aden off the Somali coast.

More than 20 countries are expected to contribute to the force, called the Combined Task Force 151 (CTF-151), which will be headed by U.S. Navy Rear Admiral Terence McKnight. The force is expected to be operational by mid-January, according to a statement released by the U.S. Fifth Fleet from Bahrain.

More than 100 ships were attacked in the Gulf of Aden last year by Somali pirates, but the International Maritime Institute reported that increased patrols had reduced the number of hijackings in December. Recently, a Greek oil tanker used water cannons to fight off a pirate attack.

U.S. Vice Admiral Bill Gortney, the commander of Combined Maritime Forces, a multinational naval coalition based in Bahrain, said merchant ships had been “doing a great job stepping up and utilizing these methods to defeat piracy attempts."

But he cautioned that naval efforts would not end piracy: "The problem of piracy is and continues to be a problem that begins ashore and is an international problem that requires an international solution," he said.

The force does not have a mandate to pursue pirates on land in Somalia. However, Abdirahman Mohamed Farole, the newly-elected president of the semi-autonomous territory of Puntland – which serves as a base for many of the pirates – has vowed to crack down on them.