Italy's foreign minister says three Italian shipmen and one Ukrainian kidnapped Dec. 23 off Nigeria's coast have been freed.

Minister Giulio Terzi said in a statement Wednesday that the three Italians would be returning home to Italy soon.

Gunmen had attacked their supply ship, the Asso21 operated by Naples-based shipping company Augusta Offshore SpA, and taken the men hostage on Dec. 23 as they sailed off the coast of Bayelsa state. It was the latest attack in the West African region that is increasingly dangerous for shippers and oil companies.

Terzi said their freedom was the fruit of successful diplomatic efforts by Italian and Nigerian officials.

Speaking to RAI state radio, Terzi said the attack was unusual in that the gunmen didn't seize the ship, but rather just took the men hostage. They were all crew members of the ship.

He said 30 Italians who had been kidnapped in similar incidents in recent months had been freed.