A Somali man who acted as a ransom negotiator for pirates who seized an American yacht last year and killed four American hostages was sentenced on Monday by a US federal judge to serve 12 life sentences.

Mohammad Shibin was convicted in April on 15 charges including piracy, hostage taking, kidnapping and conspiracy. He was paid $30,000 to $50,000 in cash for his negotiating services, according to a federal indictment.

In a courtroom in Norfolk, Virginia, US District Judge Robert Doumar sentenced Shibin to serve 10 concurrent life sentences, two consecutive life sentences and two 20-year sentences and ordered him to pay $5.4 million in restitution.

"Mohammad Shibin was a key participant in two of the most heinous acts of piracy in modern memory," US Attorney Neil MacBride said in a statement.

Please LIKE our Facebook page - it makes us stronger