ExxonMobil Corp. (NYSE: XOM) said on July 12 no attacks had taken place at its facilities after Nigerian militant group Niger Delta Avengers said it had blown up the Qua Iboe 48-inch crude oil export pipeline operated by the company.

"There were no attacks on our facilities," said ExxonMobil spokesman Todd Spitler.

Late on July 11, Nigerian militant group Niger Delta Avengers said on its website that it had blown up an ExxonMobil facility. The group has claimed responsibility for a series of attacks in Nigeria's southern oil hub.

The militants, whose attacks briefly pushed Nigeria's crude production to 30-year lows in spring, have said they want a greater share of the OPEC member's energy wealth to go to the impoverished southern Niger Delta, the source of most of the country's oil.

Qua Iboe is Nigeria's largest crude oil stream and exports usually amount to more than 300,000 barrels per day.

Nigeria is typically Africa's biggest oil producer, although attacks in the last few months have pushed it behind Angola. The West African country relies on crude oil sales for around 70% of government revenues.