Nigerian militants have attacked an oil pipeline in the oil-producing Niger Delta region.
The attack on Monday was the second in four days in Delta State - on Friday gunmen blew up a pipeline belonging to the American oil giant Chevron.
On Monday Chevron confirmed that the attack on its pipeline had caused them to stop pumping 11,500 barrels of oil.
Nigeria is Africa's largest producer of oil, but militants have cut production by around a fifth since 2006.
But militant attacks have not had the same influence on oil prices as they did when demand was higher in past years, analysts say.
It was not immediately clear which company operates the flow station attacked in Monday's raid.
"The facilities remain intact, there were no casualties to our troops," Lt Col Rade Abubakar, Delta State spokesman for the Joint Military Task Force told Reuters news agency.
Oil spikes
Nigeria pumps 2.16 million barrels of crude per day, according to the Nigerian National Oil Corporation (NNPC), but analysts say the figure is actually under two million barrels.
Crumbling oil infrastructure and militant attacks have held production back from Nigeria's theoretical capacity of around 2.7 million barrels for several years.
In previous years militant attacks have caused spikes in the oil price, as Nigerian crude was in high demand because of its quality, but with crude prices at low levels, demand for premium Nigerian crude has dropped.
Cuts in production quotas made by oil cartel Opec are due to be enforced in the next few months, and if militant attacks continue they could again cause spikes in the oil price, traders say.
Militants in the Niger Delta say they are fighting for a fairer share of the oil revenue, but many are criminal gangs who operate as armed security for oil theft syndicates who also fund themselves through kidnapping and extortionThis article is from the BBC News website. © British Broadcasting Corporation