NEW ORLEANS - A coalition of mayors of cities and towns along the Mississippi River says it has added new organizations to an international pledge to protect the world's rivers in the face of threats from climate change and population growth.

The Mississippi River Cities & Towns Initiative says new groups signed the pledge Thursday at an assembly of the International Network of Basin Organizations in Merida, Mexico.

The new signatories are the North American Network of Basin Organizations, the Brazilian Network of Basin Organizations, the Mediterranean Network of Basin Organizations and the African Network of Basin Organizations. Those groups represent more than 70 nations.

Signatories pledge to fight river pollution, urban runoff and harmful agricultural practices while also planting new vegetation.