PORT HARCOURT, Nigeria, May 6 (Reuters) - Unknown gunmen have kidnapped a Russian oil industry contractor in Nigeria's main oil city of Port Harcourt, security sources said on Sunday. The latest abduction brings to 28 the number of foreign workers kidnapped in the world's eighth largest oil exporter in three attacks this week. Eight were released. The woman, who is a senior executive with catering contractor Whassan Eurest Nigeria Limited (WENL), was abducted on Saturday night in the exclusive GRA district of the city.
