Over 100 armed militants on Thursday attacked and took over a Nigerian oil flowstation operated by US oil giant Chevron, a company spokesman told Xinhua, as tension in African top crude producer's oil delta built up over the arrest of their leader.

"A large crowd of people, some of them armed, came to the flowstation this morning," Edith Azinge said, noting that there was no injury during the occupation of Idama flowstation in the oil-rich Niger Delta by militants of illegal Niger Delta People's Volunteer Force (NDPVF).

"We have shut the flowstation in the interest of our oil workers ... evacuating non-essential personnel from nearby facilities as a precautionary measure," she said.

The Idama flowstation is only producing about 8,000 barrels of crude per day but the militants had threatened to attack all oil installations if their top leader Alhaji Mujahid Dokubo Asari would not be released soon.

"We will continue to monitor the situation very closely and will make decisions as circumstances dictate," Azinge said.

Asari was arrested in Port Harcourt, the hub of Nigeria's oil operations in the southern Niger Delta, where the majority of the country's oil is produced, and flown to the capital Abuja on Tuesday.

Police said Asari was arrested over "seditious and treasonable" comments and could face treason charges.

In a recent exclusive interview given to the Daily Independent, a leading daily newspaper in Nigeria, Asari said: "Nigeria is an evil entity. It has nothing to stand on and I will continue to fight and try to see that Nigeria dissolves and disintegrates."

The separatist militant group last year threatened to launch an overall war against foreign oil companies which helped increase the price of crude to 50 US dollars a barrel.

Nigeria is the largest oil producer in Africa and the eighth largest oil exporter in the world with the output of crude of over 2.5 million barrels per day.

Source: Xinhua