Authorities say gunmen have abducted a British oil worker from a drilling rig off the coast of Nigeria.

A spokesman for the U.S.-based operator, Transocean, said the attackers Saturday boarded the "Trident Eight" rig and seized one of the workers. The spokesman said the other 23 people on the rig were left unharmed.

Such kidnappings are common in the region, where criminal gangs are active, and where militants have demanded that the government give more of the region's oil wealth to impoverished locals.

Nearly 200 foreign workers have been abducted over the past year in the region. Most have been released unharmed, often after a ransom was paid.

The attacks have forced the shutdown of oil facilities, crippling Nigeria's oil industry.

Some information for this report was provided by AP and Reuters.