'Talks' to end Nigeria oil crisis
Asari wants the Ijaws to benefit more from Nigeria's oil wealth
The leader of a militia based in Nigeria's main oil region says he is to meet the president following his threat to attack foreign oil workers.
Dokubo Asari told the BBC that he has gone to the capital, Abuja, with five other members of his armed group.
His threat was one reason why world oil prices reached a record high of $50 a barrel this week.
He says he is fighting for the rights of the Ijaw people but the authorities have dismissed him as an oil thief.
Mr Asari says he flew to Abuja on a presidential jet and that the meeting was at the request of an envoy from President Olusegun Obasanjo who travelled to the creeks in the Niger Delta to see him.
But there has been no confirmation of the talks from the government.
On Tuesday, Nigeria's military warned Mr Asari's Niger Delta People's Volunteer Force that it would take off the "kid gloves" unless the militia stops threatening oil workers.
The militia said foreign oil companies must cease production or face "all-out war" in the Niger Delta from 1 October.
In pictures: Fighting for oil
Anglo-Dutch oil company, Shell, the biggest oil company in Nigeria, has boosted security following the threats.
Nigeria is the world's seventh largest exporter of oil, but 70% of the population live in poverty.
A statement from Shell described the region as still tense and said that the movement of employees and supplies had been curtailed.
Oil production has also been affected.
The Santa Barbara flow station, which produces 28,000 barrels per day, has been shut down because the company cannot reach the area to fix a technical problem.
Mr Asari said that expatriates - who in this region are predominantly oil workers - could only return when fundamental issues of resource control and self-determination had been resolved.
He took to the creeks of River State earlier this year, and hundreds of people have died in the subsequent clashes with the police, navy and rival gangs.
Fighting has intensified in the last month after the military launched a major operation against the group.
Clashes between rebels and security forces have escalated
Last week, Shell pulled out more than 200 of its non-essential staff from two gas and oil fields because of heightened tensions.
A spokesman for Rivers State government called Dokubo Asari a "joker".
"He does not have the capacity to destroy oil installations. The government will not allow it. The security forces are fully mobilised and combat-ready to dislodge this criminal group," Emmanuel Okah told AFP news agency.
The BBC's Anna Borzello in Nigeria says the Niger Delta holds the bulk of Nigeria's oil reserves, but the area is under-developed and riven by conflict, often caused by armed gangs involved in the lucrative trade of smuggling crude oil.