Maritime officials say pirates have seized two more ships as they were navigating through the waters near Somalia.

The chief of the International Maritime Bureau in Kuala Lumpur Noel Choong said pirates hijacked a Greek carrier, the "Centauri," south of Mogadishu Thursday.  The ship was headed to Kenya with a crew of 25.

A Kenyan maritime official, Andrew Mwangura, said pirates also seized a ship from Hong Kong early Thursday.

He said that ship, the "Great Creation," was on its way to India from Tunisia when captured off the Somali coast.  The vessel also has a crew of 25.

Officials say both ships are being taken towards Eyl, a pirate's lair on the Somali coast.

Somali pirates are now believed to be holding more than a dozen ships and their crews hostage.

Earlier this week, French President Nicholas Sarkozy called for stronger international action to stop the pirates.  With the two latest hijackings, 56 vessels have been attacked off the coast of Somalia this year.

The Somali government is fighting an Islamist insurgency and lacks the power or resources to stop the hijackings.

An international naval force patrolling the Somali coast has had little impact on the pirates' activities.

Spain says it is sending a military aircraft to Somalia to guard against further hijackings.  The plane will relay any information it gathers to a European Union task force created to deal with the issue.

Some information for this report was provided by AFP, AP and Reuters.