A second oil pumping station has been closed in Nigeria's oil-producing Niger Delta region, following threats by militant groups.
Asari accused the government of being a dictatorship
On Thursday, more than 100 armed men in boats stormed a flow-station, sources close to the Chevron oil company said.
The unrest follows the arrest of militia leader Mujahid Dokubu-Asari, who has been remanded in custody for two weeks by a judge in Abuja.
He wants more control of oil resources for the Ijaw people of the Niger Delta.
A Chevron spokeswoman said the Robertkiri station had been shut "based on our assessment that it was under imminent threat".
The spokeswoman said that the Idama station, which was stormed on Thursday, had now been vacated.
Together, the two stations account for less than 1% of Nigeria's normal output of 2.5m barrels a day.
The deputy leader of the Niger Delta People's Volunteer Force, Alali Horsefall, has threatened to blow up the stations they occupy unless Mr Asari is released.
The militia has warned all foreign oil-workers to leave the area.
At his first appearance in court since being arrested on Tuesday, Mr Asari said the government was acting like a "high dictatorship" after his lawyer, Uche Okoko, was also detained.
Justice Minister Bayo Ojo said Mr Asari would be charged with "treason and unlawful assembly".
Mr Okoko, the lawyer, is expected to face similar charges - he was outraged at his treatment.
"I came from Port Harcourt to bail him out and I've been arrested for treason," he shouted to reporters as he was led off.
A police spokesman said Mr Asari was being held over a newspaper interview, in which he allegedly said he would continue his fight until Nigeria dissolves.
Last year, the Niger Delta People's Volunteer Force contributed to a sharp rise in world oil prices when it threatened war against oil companies.
The Niger Delta remains one of Nigeria's poorest and least developed regions, although it accounts for most of the oil produced by Nigeria, Africa's largest oil-producer.