Authorities in Somalia's semi-autonomous Puntland region say they have arrested 11 pirates, including one accused of involvement in the killing of several security force members last year.

Officials said the operation Sunday in Hafun also netted rifles and a heavy machine gun.

A statement identified one of the pirates as Mohamed Hassan, also known as Dhafoor, who is wanted for hijacking commercial vessels in the Indian Ocean and Gulf of Aden.

Authorities also accuse Hassan of being part of a group that killed five security forces during a failed March 2011 attempt to free a kidnapped Danish family. Pirates released the family in September.

Somalia-based pirates have hijacked dozens of ships traveling near the Horn of Africa in the past five years, and made hundreds of millions of dollars in ransom.

Attacks have declined in recent months, as ships take more protective measures and naval forces patrol the coastline more closely.