Somali officials say pirates have hijacked a ship off the coast of the Horn of Africa nation.

One official in the semiautonomous state of Puntland says the incident occurred on Monday. The official says over two dozen men boarded the merchant ship off Somalia's northern coast.

Another official in Puntland says the ship is a Sri Lankan-flagged freighter and is now being moved toward the coast.

Both officials spoke on condition of anonymity because they were not authorized to speak to the press.

A spokeswoman for the European Union Naval Force operation off Somalia, Flt. Lt. Louise Tagg, confirms that an incident involving an oil tanker has occurred off the coast of Somalia and an investigation is underway.

Piracy has lessened off Somalia's coast in recent years.