Liza Ali, a spokesman for the vessel's owner, Masindra Shipping, told Malaysia's Bernama news agency that the tugboat had been released Sunday, but said it remained in a zone considered to be 'dangerous' and refused to comment further.

Media reports said the hostage-takers received a ransom.

The Masindra was captured in December at the tail-end of a spike in pirate activity in the busy shipping lane off the Somali coast, which links Asia with Europe.

Many of the piracy attacks end with the payment of a ransom.