The Foreign Office later confirmed that two of the men were engineers, David Welsh, 63, who is resident in Spain, and Keith Miller, 50. The men, who are employees of Niger-Benue Transport Company, were seized on Monday outside the firm's premises in East Warri, in the Delta region. Two others had been captured during a ship hijack in the Niger delta on August 6. Four other British men kidnapped in this incident were released in Port Harcourt. A spokesman for the Foreign Office said some of the kidnapped men were oil company workers, and that this was the latest in a series of abductions of foreign and British nationals in the area.
Last month, a Briton and an Australian working for Royal Dutch Shell in Nigeria were released three weeks after they were taken hostage with their helicopter in the Delta area.
Resentment against the multinational energy firms has been a long-running feature of the oil-rich west African country, where many locals complain that few profits reach ordinary people.
The Foreign Office's travel advice, which was stiffened last week, warns Britons working in the country's oil and gas industries that they run the risk of being held captive, either by protesters or even their own colleagues during industrial disputes.
There have already been a number of similar incidents this year, although all the Britons involved were eventually set free unharmed.
Last month, a British pilot working for an oil firm in the Delta region was set free after three weeks in captivity. Four days earlier, Briton Tommy Mitchell and two Shell colleagues were released.Reuse content