ONITSHA, Nigeria (Reuters) – Gunmen in Nigeria’s restive southern Niger Delta region, which has been hit by a series of militant attacks on energy facilities since the start of the year, have kidnapped 14 local oil workers and their driver, police said on Saturday.

Kidnapping for ransom is a common problem in some parts of Nigeria and the southern Delta energy hub has seen an increase in crime since the start of attacks by militants calling for more oil wealth to go to the impoverished region.

The abduction took place on a road connecting the towns of Omoku and Elele, around 50 km (30 miles) from the city of Port Harcourt, Rivers state, in the early hours of Friday as the employees of Nigerian energy company Nestoil travelled to work, police said.

“We have recovered the vehicle they were travelling in before the incident occurred. Police are currently combing bushes around the area in a bid to find and release the victims,” said Nnamdi Omoni of Rivers state police.

“I do not think there was a foreigner among those kidnapped. Their abductors have not made any contact and nobody has been arrested yet,” added Nnamdi.

A spokesman for Nestoil could not immediately be reached.