Colonel Rabe Abubakar, spokesman for the joint military taskforce in the eastern Niger Delta, said troops discovered oil spillages from a burst oil pipeline near the border of Bayelsa and Delta states in southern Nigeria.

"The spillages in these communities were an act of sabotage," he said. "Evidence around the spillage area showed that illegal oil bunkerers were again in operation."

Nigeria is the world's eighth biggest exporter of crude oil but thieves take a sizeable proportion of its output by drilling into pipelines or hijacking barges loaded with oil, theft known locally as "bunkering".

Some estimates say 100,000 barrels of crude are stolen from the Niger Delta each day, about five percent of the country's production and equivalent to around $4 million daily or $1.5 billion a year at current prices.