This has led to "systematic and severe constraints on Palestinian development of water resources", says the report.

But the Palestinian Authority (PA) too gets part of the blame. It is struggling to establish even a basic water infrastructure and management, concludes the report.

Water supplies continue to "operate in a very inefficient emergency mode, with far reaching economic, social and environmental consequences".

Since biblical times Jewish communities lived in Arab lands, in Persia, India, East and North Africa and indeed in Palestine.

President Obama, facing criticism at home for appearing too cozy with President Hugo Chávez of Venezuela, defended his overtures on Sunday, saying the handshakes and polite conversation the two leaders shared here were hardly “endangering the strategic interests of the United States.”

Mr. Obama, wrapping up a four-day swing through Latin America that included a summit meeting of Western Hemisphere leaders here, said he believed he had paved the way for “frank dialogue” with countries like Venezuela and Cuba, countries whose relations with the United States are, respectively, strained and practically nonexistent.