Pirates attacked an Italian ship off Nigeria and kidnapped four crew members on Sunday night.
AAP reports three of those abducted were Italians, but the nationality of the fourth was not yet clear.
The International Maritime Bureau said the attack occurred 40 nautical miles off the coast of Bayelsa state.
The Nigerian navy named the ship as the MV Asso Ventuno and said five vessels had been deployed to patrol the area.
The IMB said the Asso Ventuno continued its passage to a safe port
AAP reports such kidnappings occur regularly off the Niger Delta region and the hostages typically released after payment of a ransom.