Aug 10 (Reuters) - Gunmen seized a British manager from the anarchic Nigerian city of Port Harcourt in the Niger Delta on Friday, authorities said.

About 200 adult expatriates have been kidnapped in the Niger Delta since the start of 2006 and Friday's incident raises to at least five the number of foreigners being held captive by armed groups.

Below is a chronology of some major attacks and kidnappings involving the Nigerian oil industry since President Umaru Yar'Adua was sworn in on May 29.

-- June 3 - Gunmen kidnap six staff of United Company RUSAL, the Russian aluminium giant, in Ikot Abasi in the southeast. The men were working at the Aluminium Smelter Company of Nigeria. They are released on Aug. 7.

-- June 15 - Gunmen kidnap two Lebanese men, working for Italian firm Stabilini, near Ogara in Delta state.

-- June 16 - Militants release 10 Indian hostages held since June 1. The hostages included at least three senior executives of Indonesian petrochemical company Indorama.

-- June 23 - Four hostages, from Britain, France, the Netherlands and Pakistan, employed by oil services giant Schlumberger are released unharmed. The men were abducted on June 1 from Port Harcourt.

-- June 25 - Two Indian construction workers, kidnapped near Sapele in Delta State on June 15, are freed.

-- July 4 - Armed men attack a Shell facility at Soku and abduct five expatriates, two from New Zealand, one Australian, one Venezuelan and one from Lebanon. They are released on July 11.

-- July 5 - A 3-year-old British child, Margaret Hill, is abducted in Port Harcourt. She is released on July 8.

-- July 7 - Oil major Royal Dutch Shell said one of its teams had been attacked in Rivers state in the delta and two Nigerian workers taken hostage. The Nigerians are released on July 11.

-- July 12 - Francis Samuel Amadi, the 3-year-old son of a traditional ruler in the community of Iriebe, is kidnapped near Port Harcourt. He is released the next day.

-- July 31 - A Pakaistani man, a manager in charge of dredging on a construction site run by Italian firm Gitto, is kidnapped near Bodo community in the Ogoni area of Rivers state.

-- Aug. 8 - Kidnappers release a Bulgarian and a Briton, employees of British oil company Exprogroup. They were abducted on July 8 from a barge near Calabar in Cross River state.

-- Aug. 10 - Gunmen seize a British manager from oil services firm Hydrodive in Port Harcourt.

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