The militant, Henry Okah, potentially faces the death penalty for his alleged crimes, according to judicial officials. While the proceedings kicked off last week, the court is officially adjourned until April 22.
His lawyer has criticized the secrecy imposed by Nigerian courts.
"This is a case of gun-running and it does not warrant this kind of trial," Okah's chief defense lawyer, Femi Falana, said earlier this month.
Prosecutors say Okag is a key member of the Movement for the Emancipation of the Niger Delta, which claims credit for attacks on foreign oil installations over the past two years that have resulted in production in Africa's No. 1 supplier by as much as 33 percent.
Some Nigerian leaders have denounced the case. Edwin Clark, a leader of the Ijaw tribe in the delta, said the government's course of action showed its lack of control over the delta and that he would sue federal leaders if the trial was not made public.
"The application of a different law to the people of the Niger Delta clearly gives the impression that the Federal Government has lost control over that part of the country and was not exercising sovereignty over the area, and therefore has to apply separate laws to them," he said earlier this week. "You can only apply different laws in an area where you have no control."
Okah was picked up in Angola Sept. 3 on weapons-trafficking charges, which MEND said were trumped up by Nigeria and Angola. Both nations' leaders have denied the accusations.
While most MEND members and its leadership received guarded praise from Nigeria's new leadership for initiating a cease-fire, Okah reportedly continued to wage violent attacks and denounced the end of hostilities while continuing a weeks-long battle with rival groups in the streets of the oil-rich Niger Delta's largest city, Port Harcourt.
MEND and other militant groups have been blamed for hundreds of kidnappings since violence in the delta began in 2005. Increased violence against oil operations in the delta has caused significant drops in the country's oil output, according to the Nigerian government and independent accounts. Before stepped-up hostilities by militant and other armed groups in the Niger Delta beginning in late 2005, Nigeria claimed to be producing about 2.5 million barrels per day. Since then, production has reportedly decreased by at least 20 percent, perhaps even by one-third, warn some analysts.
Since the 1970s, Nigeria, Africa's No. 1 oil producer, has pumped more than $300 billion worth of crude from the southern delta states, according to estimates. High unemployment in the delta, environmental degradation due to oil and gas extraction, and a lack of basic resources such as fresh water and electricity have angered the region's youth, who have taken up arms, many times supplied by political leaders, and formed militant groups and local gangs.
The militants have called for a more equitable distribution of the country's oil wealth.
Hoping to quell the violence, Nigerian President Umaru Yar'Adua reached out the rebels following his April election asking for them to give his administration time to tackle the problems of the delta. Those proposed reforms include changes to the Nigerian economy, particularly its petroleum sector, which generates up to 95 percent of the country's revenue.