The commander of the European Union Naval Force says Somali pirates have begun systematically torturing hostages and using them as human shields.

Maj. Gen. Buster Howes said Tuesday that pirates have recently tied hostages upside down and dragged them in the sea, locked them in freezers, beaten them and used plastic ties around their genitals.

He says the pirates are using hijacked vessels as platforms to launch attacks more frequently because they know Western navies will be more reluctant to intervene if there are hostages onboard.

Eleven pirated ships deployed to hunt new prey in the six days after Christmas.

Howes said that pirates also had set fire to ships where crews were hiding in a safe room.