Lagos — A barge laden with thousands of tonnes of stolen crude oil has sunk near Shell's Forcados oil terminal in Delta State, off the coast of Nigeria, a military spokesman has said.

Spokesman of the Joint Task Force (JTF) in the area, Lt. Col. Rabe Abubakar, told the BBC yesterday that the barge was scuttled by its crew who fled before they could be arrested by the security forces.

"None of the crew members was arrested as they had swam to safety before the arrival of security agents," Lt. Col. Abubakar said.

It was suspected that the crew may have been tipped off that they were being pursued by the military, apparently due to their strong military and political connections.

The Federal Government loses billions of dollars of revenue yearly to crude oil theft, known as "bunkering."

The barge, which was said to be carrying 2,000 tonnes of allegedly stolen crude oil, also caused some environmental damage as it sank near the Forcados oil terminal, operated by Royal Dutch Shell's joint venture with Nigerian National Petroleum Corporation (NNPC).

Col. Abubakar confirmed that the vessel discharged its crude contents into the river and the spillage was causing damage to the environment, stressing that the spill had not been contained.

According to estimates by Shell 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 $6 million daily or $2.2 billion a year at current prices

Shell said that the theft of oil in the country, ranged from 20,000 to 100,000 barrels per day, stressing that at oil price of slightly more than $40 for a barrel of benchmark Brent crude, this equates to between $300 million and $1.6 billion (£1.1 billion) a year.

According to reports, one method for stealing crude oil involves boring holes in the thousands of miles of pipelines that crisscross the Delta and inserting valves - a highly risky practice that often results in explosions and deaths.

Crude is also stolen by organised criminals who steal directly from the wellhead.

Stolen Nigerian crude is usually exported by barge for refining in other parts of West Africa , Brazil and Eastern Europe. The Nigerian military said it had mounted several successful operations against oil thieves, including the arrest of a crew of Filipino sailors in 2008.

They were sentenced to five years in jail, but were then released after paying a fine.