The start of the treason trial of Nigerian oil militant Mujahid Dokubo-Asari has again been delayed after angry rows in court.
Mujahid Dokubo-Asari says locals should benefit from the oil
Mr Asari was shouting and swearing, saying his life was in danger while in custody, prompting the prosecution to ask him to be barred from the trial.
Three of his wives were crying, while hundreds of his supporters gathered at the High Court in the capital, Abuja.
He was arrested in 2005 after calling for the oil-rich Niger Delta to secede.
The BBC's Senan Murray in the capital, Abuja, says the government is under pressure to release Mr Asari - a key demand of those who have staged a wave of attacks on oil facilities in the region.
Last year, Nigeria lost some $4bn because of unrest in the Niger Delta.
There was tight security outside court, with a truckload of riot police on standby in case of any trouble.
Mr Asari said that his weight has gone down from 139kg to 93kg while in custody, and further said he was being held in an underground cell, without access to his lawyers and family.
His first wife Mujahidat Dokubo-Asari said she had not been allowed to see her husband, warning that "Nigeria will regret it" should her husband die in custody.
"If anything happens to my husband, I assure the federal government that within 48 hours, all oil exploration in the Niger Delta will be stopped whether [President] Obasanjo likes it or not," she said.
The prosecution, meanwhile accuse Mr Asari of unruly behaviour.
"At the last two sittings of the court the accused rained chains of vitriolic... utterances on the honourable judge and the prosecution," they said in a written motion arguing for him to be barred.
"The accused person went to the extent of threatening to snatch... the rifle and pistol of the police and prison guards to use them on the honourable judge and the director of public prosecution," the document read.
Last week, Nigeria army chief of staff Major General Andrew Azazi, who is from the Delta, met some oil militants, who repeated their demand for Mr Asari's release if the violence is to stop.
They also want former Bayelsa State governor Diepreye Alamieyeseigha to be freed - he is accused of corruption and money laundering.
The militants often attack oil installations and kidnap oil workers for ransom.
Last year, such attacks cut Nigeria's oil output by some 20%.
Nigeria is Africa's biggest oil producer but most of the Niger Delta population remain poor.
The militants say more of Nigeria's oil wealth should benefit local people.