Shell said Sunday sabotage of pipelines by oil thieves in southern Nigeria was on the increase and had led to halts in production without providing details on the amount of crude lost.
"Between August 1 and 12 this year alone, (Shell) recorded three separate sabotage incidents on its Cawthorne Channel - Bonny and Alakiri - Bonny pipelines, where suspected crude thieves drilled holes or inflicted hacksaw cuts to siphon oil," the company said in a statement.
A Shell spokesman could not specify the amount of oil spilled.
"Each time there's an oil spill, we shut down production to repair the line," he said. "We've had three attacks - two have been repaired and production has been restored. On the third one we are about to commence repairs."
Oil thieves in Nigeria often sabotage pipelines and take the stolen oil to illegal refineries.
Militants in the country's south have also carried out repeated attacks on pipelines and other industry targets in the country's south in recent years, demanding a fairer distribution of oil revenue.
The attacks led to a sharp decline in production in the world's eighth largest oil exporter, but an amnesty deal offered to militants last year has greatly reduced the number of incidents. Production has also increased.