(Adds Nigerian police comment) ONITSHA, Nigeria, April 15 (Reuters) - An Italian construction worker kidnapped last week in southeastern Nigeria was released by his captors on Wednesday, the Nigerian police and Italian Foreign Ministry said. The man, who was not identified, was working for a construction firm on a state government contract when he was abducted in Ebonyi state on April 6, police said. "He was released in the early hours of this morning through the joint efforts of the police and SSS (state security service)," Ebonyi state police commissioner Emmanuel Udoji said. "Three persons were arrested in connection with his kidnap. They demanded a ransom earlier, but none was paid to them," he told Reuters. The Italian Foreign Ministry thanked Nigerian authorities in a statement for their "active cooperation which led to the positive resolution of this incident." Abductions are common in the creeks of the Niger Delta, the heartland of Nigeria's oil and gas industry which lies just south of Ebonyi, but comparatively rare in other parts of Africa's most populous country. More than 200 foreigners have been seized in recent years in the Delta. Most have been freed unharmed after a ransom payment. (Reporting by Anamesere Igboeroteonwu in Onitsha and Daniel Flynn in Rome; Editing by Nick Tattersall)