LAGOS, Feb 19 (Reuters) - Gunmen kidnapped three Croatian oil workers in Nigeria's oil city of Port Harcourt, oil industry security sources said on Monday. The abduction, in the city's Iwofe district late on Sunday, raised to nine the number of foreigners held by different armed groups in the Niger Delta, Africa's top oil-producing region. An American engineer and his Nigerian driver were released by their captors on Saturday.
