Peru’s indigenous leaders have sent a letter to Pope Francis urging him to press for the clean-up of polluted rivers and recognition of ancestral land rights during his visit to the Amazon.

Three umbrella organisations representing the Amazon’s indigenous communities have asked the pontiff to support their demands that Peru’s government clean up wide swathes of land tainted by mercury from illegal gold mining.

The leaders also want Francis to back their call for the state to grant 20 million hectares (77,000 square miles) in collective land rights to indigenous groups.

That is an area roughly equivalent in size to Senegal.

An estimated 4,000 people from indigenous groups throughout South America will gather to hear the pontiff speak on Friday in the Peruvian Amazon.

Many are hoping Francis can serve as a bridge between native peoples and the government.