U.S. and international officials said about half of the countries indicated they planned to enrich or reprocess nuclear fuel, leading to possible expansion of the worldwide supply of plutonium and enriched uranium, The Washington Post reported Monday.

Rising fuel cost is driving some of the decisions, experts said. But in oil-rich Middle East, interest in nuclear programs could be linked to concerns about a regional arms race, officials told The Post.

"We are concerned that some countries are moving down the nuclear (weapons) path in reaction to the Iranians," a senior U.S. government official who tracks nuclear technology said. "The big question is: At what point do you reach the nuclear tipping point, when enough countries go nuclear that others decide they must do so, too?"

Mohammed ElBaradei, head of the U.N. International Atomic Energy Agency in Vienna, said pursuing nuclear capability could be considered a deterrence move.

"You don't really even need to have a nuclear weapon," ElBaradei told the Post. "It's enough to buy yourself an insurance policy by developing the capability and then sit on it."