Somali pirates have seized a British-owned freighter in the Indian Ocean, the ship's agent confirmed Saturday, dpa reported. The ship, with a Ukrainian crew and carrying 35,000 tonnes of soya, was seized around 250 miles south-west of the Seychelles. On Friday the Portuguese Navy headed off an attempted hijacking of a merchant ship off the coast of Somalia, Portuguese media reports said. The pirates were detained and weapons were seized, military officials said.