VIENNA, Austria – At least 40 developing countries, from the Persian Gulf region to Latin America, have recently approached U.N. officials to signal interest in starting nuclear power programs, a trend that proliferation experts say could provide the building blocks of nuclear arsenals in some of those nations.

At least half a dozen countries have also said in the past four years that they plan to conduct enrichment or reprocessing of nuclear fuel, a prospect that could dramatically expand the global supply of plutonium and enriched uranium, according to U.S. and international nuclear officials and arms control experts.

Much of the new interest is driven by economic considerations, particularly the soaring cost of fossil fuels. But for some Middle Eastern states with ready access to huge stocks of oil or natural gas, such as Kuwait, Saudi Arabia and the United Arab Emirates, the investment in nuclear power appears to be linked partly to concerns about a future regional arms race stoked in part by Iran’s alleged interest in such an arsenal, the officials said.

“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 the spread of nuclear technology said in an interview.

He declined to speak on the record because of diplomatic sensitivities. “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?”

Although the United Arab Emirates has a proven oil reserve of 100 billion barrels, the world’s sixth-largest, in January it signed a deal with a French company to build two nuclear reactors. Wealthy neighbors Kuwait and Bahrain also planning nuclear plants, as are Libya, Algeria, Morocco and the kingdom of Jordan.

Even Yemen, one of the poorest countries in the Arab world, last year announced plans to purchase a nuclear reactor, which it says is needed to produce electricity.

Egypt’s ambassador to the United States, Nabil Fahmy, told a recent gathering of Middle Eastern and nonproliferation experts that his country’s decision was unrelated to Iran’s nuclear activities. But he acknowledged that commercial nuclear power “does give you technology and knowledge,” and he warned that a nuclear arms race may be inevitable unless the region’s leaders agree to ban such weapons.

Many countries involved in nuclear expansion have stressed their peaceful intentions. Some, such as the United Arab Emirates and Bahrain, publicly vowed never to pursue uranium enrichment or fuel reprocessing, technologies that can be used to create fissile materials for nuclear weapons. But some arms-control experts say the sudden interest cannot be fully explained by rising oil prices.

“This is not primarily about nuclear energy. It’s a hedge against Iran,” said Ploughshares Fund president Joseph Cirincione, an expert on nuclear policy and author of “Bomb Scare: The History and Future of Nuclear Weapons.”

“They’re starting their engines. It takes decades to build a nuclear infrastructure, and they’re beginning to do it now. They’re saying, ‘If there’s going to be an arms race, we’re going to be in it.’”