All seven foreign oil workers who were being held hostage in Nigeria's southern Niger Delta have been released and are in good health, police said on Saturday, according to Reuters. The men are four Britons, one Romanian, one Malaysian and one Indonesian. They were kidnapped on Oct. 3 in an unprecedented raid on a residential compound for expatriate contractors working for U.S. oil giant Exxon Mobil. "All seven have been released. They are all in good health," said Suur Chafa, deputy superintendent of police in Akwa Ibom state, where the men were kidnapped. "They have already been taken to Port Harcourt where the state security services will release them to their various companies," he said. Port Harcourt, located in neighbouring Rivers state, is the main city in the Niger Delta. The vast wetlands region, home to Africa's biggest oil industry, has been plagued by attacks on oil facilities and abductions of oil workers this year. A fifth of Nigeria's production capacity has been shut down since February due to militant attacks.