Gunmen have kidnapped 15 oil workers on a road near Nigeria's oil hub of Port Harcourt, police said on Saturday, in the latest unrest in the restive region.

‘Fifteen oil workers, including their driver, were abducted yesterday (Friday) by unknown gunmen who hijacked their vehicle on Omoku/Elele road after shooting into the air to scare passersby,’ Rivers state police spokesman Nnamdi Omoni told AFP.

He said the workers who were employees of Nestoil, an oil and gas service firm, were on their way to their office in Port Harcourt when they were seized.

Omoni said police was on the trail of the gunmen.

‘We are combing the bush and creeks in the area. Our men are all over the place. We are doing our best to rescue the victims and apprehend the kidnappers’, he said.

Omoni said police had recovered the bus after it was abandoned by the gunmen.

Kidnappings targeting prominent Nigerians and foreigners, especially in the oil-producing south, was rife in the 2000s until a 2009 government amnesty reduced unrest in the region.

A resurgence of violence since the start of the year has seen a wave of devastating attacks on Nigeria's oil infrastructure that have slashed output and hammered government revenue.

Nigeria which normally gets 70 percent of government revenue from oil, has slipped into a recession, while inflation has surged to 17.1 percent, its highest in more than a decade.