Jan 18 (Reuters) - Six hostages in Nigeria, five Chinese and one Italian, were released on Thursday by two different groups in the oil-producing Niger Delta. Following is a chronology of some major attacks on the Nigerian oil industry in the last three months. Oct. 2, 2006 - Twenty-five Nigerian staff of a Royal Dutch Shell contractor are abducted after a raid on boats carrying supplies to Shell facilities in the Cawthorne Channel in Rivers state. They are released two days later. -- Oct. 21 - Seven foreign oil workers held hostage since Oct. 3 are released. The men, four Britons, one Romanian, one Malaysian and an Indonesian, were kidnapped in a raid on a compound for expatriate contractors working for Exxon Mobil. -- Nov. 7 - An American and a Briton, working for Petroleum Geo-Services (PGS) and kidnapped from a survey ship off the coast the southern state of Bayelsa on Nov 2, are freed. -- Nov. 22 - A British oil worker is killed when Nigerian troops try to free seven foreigners abducted from an offshore oilfield earlier in the day. -- Dec. 7 - Eight gunmen kidnap three Italians and one Lebanese from a residential facility after failing in their attempt to storm the Agip oil export terminal in Bayelsa state. The Movement for the Emancipation of the Niger Delta (MEND) threatens new attacks and claims responsibility. -- Dec. 14 - Armed men invade the Nun River logistics base operated by Royal Dutch Shell in Bayelsa state and hold at least five people hostage at the facility. -- Dec. 18 - Two car bombs rock Port Harcourt. One near the compound of Italy's Agip and the second in the Shell residential compound. There are no casualties. -- Dec. 21 - Armed militants storm the Obagi field facility in Rivers State, operated by Total, killing three people. Oil output is unaffected. -- Militants plant a car bomb in the Shell residential compound in Port Harcourt. Shell evacuates hundreds of expatriate staff from compounds in Port Harcourt, Warri and Bonny Island. Jan. 10, 2007 - Gunmen attack a base operated by South Korea's Daewoo Engineering and Construction in the Bayelsa state capital Yenagoa and kidnap nine South Korean workers and one Nigerian. They are freed on Jan. 12. -- Jan. 16 - Three people including a Dutch oil worker are killed when their boat, operated by South Korean firm Hyundai, was attacked on its way to the Bonny Island export terminal. -- Jan 18 - Gunmen free five Chinese telecom workers, kidnapped on Jan. 5 in Rivers State. One Italian is also released in Bayelsa state. Three foreigners remain in captivity.
