Police say Asari and could face prosecution but the news that the leader of the banned Niger Delta People’s Volunteer Force is in custody has angered his followers.
They threatened “240 hours of rage” and say they will blow up oil installations if he is not released.
Rebel leaders said fighters were moving out of the southern oil city of
Port Harcourt to bases in the surrounding mangrove swamps in order to gather arms after police ignored a rebel demand that they release Asari.
Port Harcourt is the centre of Nigeria’s multi-million-dollar oil industry, a sprawling industrial centre surrounded winding creeks and swampland.
It is home to hundreds of foreign oil workers and the local base of many multinationals.
The Anglo-Dutch energy giant Shell, the biggest firm in Nigeria’s oil industry, said it had shut down its Port Harcourt office as a precautionary measure.
Other foreign companies have gone into “lock-down”, cancelling unnecessary road trips and securing their premises, according to an official from an international security firm.
A statement from police headquarters said that the 40-year-old militant was “being questioned over seditious and treasonable publications credited to him in some newspapers.”
On September 10, the Daily Independent newspaper published an interview with Asari in which he 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 police statement said: “When confronted with the said publication, Alhaji Dokubo admitted to, and stood by, the contents of the publication. He is presently cooperating with the police and may be prosecuted if found culpable.”
“Meanwhile, the Nigeria Police has taken adequate and sufficient security measures to ensure no breakdown of law and order. We wish to re-assure all Nigerians and foreigners of their safety and the protection of oil installations,” it added.