UPDATE 2-Nigeria accuses oil delta rebel leader of crimes

(Adds lawsuit challenging Okah's detention, paragraph 8)

By Estelle Shirbon

ABUJA, Feb 21 (Reuters) - Nigerian police accused a detained rebel leader from the oil-producing Niger Delta of killings, arms dealing, oil smuggling and other crimes on Thursday, raising the prospect of a trial that could destabilise the area.

Henry Okah was extradited from Angola to Nigeria a week ago and uncertainty over his fate has already increased tensions in the anarchic and impoverished delta, home to Africa's biggest oil industry which pumps 2.1 million barrels per day.

Anger among militants over what they see as government persecution of a man they hail as a freedom fighter risks igniting a new round of violence and derailing peace talks.

"Henry Okah ... has been identified as an international gun-runner and a major oil bunkerer," the police said in a statement. Bunkering is a Nigerian term for oil smuggling.

The four-page statement was the first detailed information about Okah from Nigerian authorities since he was brought back to the country last Thursday.

His group, the Movement for the Emancipation of the Niger Delta (MEND), alleged on Tuesday he had been shot dead in detention but Nigerian President Umaru Yar'Adua's spokesman later said the rebel leader was "alive and in safe custody".

The police statement did not say where Okah was being held.