UPDATE 3-Nigeria orders closed-door trial for oil rebel

(Adds Niger Delta militants' statement paragraphs 1, 13-14)

By Shuaibu Mohammed

JOS, Nigeria, May 2 (Reuters) - A Nigerian court on Friday ordered the trial of rebel leader Henry Okah to take place behind closed doors, prompting a threat of reprisals from the armed Niger Delta militants.

Okah, the suspected leader of the Movement for the Emancipation of the Niger Delta (MEND), refused to enter a plea and told the court that he had been allowed just 30 seconds with his lawyers since his extradition from Angola in February.

Federal High Court Judge Steven Adah dismissed an appeal by Okah's lawyers against a previous decision to hold the trial in secret for security reasons and the safety of witnesses.

"The trial should be in camera. The evidence to be given in public might expose Nigeria's defence capabilities to the outside world," Adah told the court in the central city of Jos.

Defence lawyers said they would appeal against the ruling.

"The charges and list of witnesses are already in the newspapers, so why conduct the trial in secret," one defence lawyer, who asked not to be named, told Reuters.

Okah is charged with treason and gun-running and stands accused of conspiring to wage war against Africa's top oil producer. He faces the death penalty if convicted.