Six Nigerian soldiers have been sentenced to life imprisonment for selling guns and other weapons to militants and criminals in the Niger Delta. Prosecutors said the arms sales had contributed to the violence in the oil-rich region. For VOA, Gilbert da Costa filed this report from Abuja.

Security experts and rights groups have long accused some members of the security forces of secretly selling arms to militants and criminals in the Niger Delta.

A Nigerian army panel, which sat in the northern city of Kaduna, convicted the six soldiers for theft of 7,000 military assault rifles, sub-machine guns and rocket-propelled grenades between 2003 and 2007. The weaponry, worth around $1 million, was sold to militants.

Army spokesman General Emeka Onwamaegbu said the trial process was not over yet, and that the convicted soldiers could face more charges.

"I can assure you with all confidence that all our other facilities where we keep weapons are quite well protected," he said. "All those who were investigated are being tried. However, their trial is not over. They have just been sentenced on the charges that were brought against them. There are still other charges that they are standing trial for now."

Nigeria is battling an insurgency that has curtailed output in the oil-rich Niger Delta. Militants have kidnapped more than 200 local and foreign oil workers and destroyed several oil and gas pipelines and other facilities.

Efforts are being made by the government to increase the speed of development in the region.

Rebel groups have called for a more equitable distribution of the country's oil wealth. Nigeria is the world's eighth largest oil exporter, but militants' raids have cut shipment by a fifth.

The Nigerian government faces a new challenge from spiraling crime in the oil-producing Niger Delta.