France, Sept. 5 -- Oil giants stand accused of walking away from decades of pollution in Nigeria's Niger Delta without cleaning up the damage. A UN-appointed panel of experts wrote to Shell, Eni, ExxonMobil and TotalEnergies, warning the companies cannot sell off their assets and dodge their responsibilities to local communities.

The letters, sent on Sunday and published on a UN website, said the companies must provide remedies for people harmed by their operations under the UN Guiding Principles on Business and Human Rights.

The panel also said firms are obliged to use their influence to prevent abuses in their dealings with others.

Governments, the experts added, have a duty under international law to make sure companies meet these r...