The Nigerian Oil Spills Detection and Response Agency's move came in response to the Dec. 20 spill from from Shell's Bonga deep offshore field in the Atlantic Ocean, The Guardian of Lagos reported
Meanwhile, a Nigerian group, the Niger Delta Indigenous Movement for Radical Change, called the leak the region's worst in more than a decade and urged Shell to respond aggressively.
The group called on Shell to take responsibility for cleanup and respond to spill-related losses sustained by fishermen and farmers.
"We are determined to see that a proper probe panel is put in place to investigate the remote and immediate causes of the Bonga oil spillage," the group said in a release. "Right now, many of our people affected by the spillage are facing serious starvation."
The group said it is not satisfied with Shell's claims the spill has been brought under control and said it is "deeply worried by the amount of the spillage."
The Rev. Samuel Ayadi, chairman of a fishermen's group, the Akwa Ibom chapter of Artisan Fishermen Association of Nigeria, told the News Agency of Nigeria suspending fishing "has practically crippled our means of livelihood for over a week now."
Ayadi said Shell, which has its headquarters in the Netherlands, "has not said anything about our losses due to the spill, which has polluted the waters where we fish."
He said a component in dispersants Shell used to contain the spill is toxic to marine life and had wiped out the fish stock within Nigerian territorial waters.