A Dutch frigate operating off Somalia's coast has released 20 suspected pirates.

Earlier this week, HNLMS Tromp sent 13 pirates back on a dinghy. All 33 Somalis captured in three separate actions have now been freed. There was not enough evidence to keep them in detention. Their weapons have been confiscated and several of their dinghies destroyed. 

The Dutch frigate is patrolling Somalia's waters as part of a European operation, code-named Atalanta, aimed at combatting piracy.