A Nigerian security official confirmed there had been an attack on Friday on a pipeline operated by Italy's Eni in the Niger Delta region.
"There was an attack on the Obi Obi Brass Pipeline between 1 and 2 am Friday," said Desmond Agu, commander of the Nigeria Security and Civil Defense Corps in Bayelsa state, Reuters reported.
"There is an oil spill at the scene ... but the place is not on fire."
The Niger Delta Avengers militant group earlier claimed the attack.
The attack is one of several in recent weeks by militants who are targeting Nigeria’s oil infrastructure.
The militants accuse the government of stealing the resources in the Niger Delta region. Friday’s attack marks one more blow for the industry, which has suffered repeated setbacks in trying to restore supply.
The Nigerian National Oil Corporation, known as NNPC, said in its monthly results this week that production had hit a 12-month low since the beginning of its review period in April 2015.
NNPC said Nigerian output stood at around 1.8 million barrels a day in March, and that figure is likely now significantly lower.
Some analysts have estimated it now stands at around 1 million barrels a day.
Nigerian Oil Minister Emmanuel Ibe Kachikwu met with militants in May in an attempt to prevent the oil attacks, but talks were unsuccessful.
Tighter supply from Nigeria has boosted prices above $50 a barrel for most of this week. The Niger Delta Avengers have said that they hope to reduce the country’s output to zero.
The group said oil firms are responsible for pollution and say the poor swampland region fails to reap any benefit from its reserves.
They said its attacks had brought Nigeria's oil production to just 800,000 barrels per day, from 2 million bpd, without killing anyone, though they hit infrastructure feeding crude grades already under force majeure.
Buyers are also looking elsewhere to buy their crude because of delivery fears associated with Nigerian cargoes, according to analysts at Copenhagen-based Global Risk Management.
