Amnesty International released a report Thursday saying Shell Oil should commit $1 billion to start cleaning up two spills in southeastern Nigeria that have impacted the livelihoods of thousands of farmers and fishermen.

Amnesty says British lawyers representing those affected by the oil spills in the Bodo, Ogoniland area of the Niger Delta in 2008 suggested that 4,000 barrels of oil were leaked each day for 10 weeks, surpassing Alaska's Exxon Valdez spill.

Shell has admitted to the spills, but says the total spill amounted to 4,000 barrels of oil.

Amnesty says the prolonged failure of Shell Petroleum of Nigeria to clean up the Niger Delta continues to have catastrophic consequences.

The United Nations originally suggested that Shell allocate an initial $1 billion for the clean-up, claiming it will take more than 25 years for Ogoniland to recover from the spill.

Shell says criminals who sabotage oil facilities also bare responsibility for oil spills in the region.