Gunmen seized four more foreign workers amid a dramatic rise in violence that has rocked Nigeria’s southern petroleum-producing region, oil industry officials said today.

Militants in restive southern Nigeria today claimed to have bombed three major oil pipelines.

Six hostages have escaped from an oil facility in Nigeria where they had been held since armed men raided it earlier this week.

Nigerian rebels have demanded $40m (€31.5m) for the safe return of four kidnapped British oil workers.

PETROL prices are set to rise by 7c per litre within weeks after world oil prices smashed through the $50 barrier yesterday.