Prime Minister David Cameron says the U.K. has signed an agreement for Mauritius to prosecute suspected Somali pirates captured by the British navy in the Indian Ocean.

Britain has previously sealed similar arrangements with the Seychelles and Tanzania, under which the countries agree to process suspected pirates in their courts.

The U.K. had complained suspects were being allowed to walk free because there was nowhere to put them on trial. It had urged nearby countries to help and take a role in international efforts to tackle piracy.

Cameron said Friday that "pirates should be in no doubt that they will be arrested at sea, prosecuted in regional states and imprisoned."

Lawmakers previously warned that eight out of 10 suspected pirates captured off the coast of Somalia were released without trial.