VIENNA, Austria - A US push to greatly reduce UN nuclear aid to Iran as part of Security Council sanctions is facing opposition from traditional US allies in the European Union as well as from developing nations, diplomats said Tuesday.

Resistance was expected from developing nations on the board of the International Atomic Energy Agency, which provides technical assistance to Iran to bolster the use of nuclear energy. Most of those countries usually support Tehran's assertion that it has the right to develop uranium enrichment technology, a process that can create fuel for energy but also the fissile material for nuclear warheads.

But any European opposition could erode attempts to present a unified Western front on dealing with Iran's nuclear defiance. The sanctions imposed on Iran last month for refusing to suspend uranium enrichment came after months of wrangling between Russia and China - which favored lighter penalties - and the US and European countries, which wanted tougher ones.

The sanctions, which fell short of the harsher measures the Americans had sought, included a review of more than 15 IAEA technical aid programs to Iran. Mohamed ElBaradei, chief of the Vienna-based UN nuclear monitor, is preparing a report on what - if any - of the programs to cut.

Several diplomats said disagreements have arisen between the US and other IAEA members seeking broad reductions and those with a more moderate views.

"The Americans said at least 50 percent of the technical cooperation programs now in place with Iran will not go through" the IAEA review, said a diplomatic representative to the IAEA, one of seven who spoke to The Associated Press on condition of anonymity for discussing confidential information.

Such a stance is opposed by Germany and many other EU nations, the diplomats said, adding that unless Washington moderates its stance confrontation is inevitable at the next IAEA board meeting in March.

A US diplomat disputed that there were major differences between the Europeans and the US, saying both wanted "an unambiguous implementation" of the Security Council resolution.

In November, the 35-nation IAEA board suspended a project to help Iran install safety measures for a heavy water reactor that will produce plutonium, another potential pathway to nuclear arms.

But the other programs up for review have less obvious potential weapons applications, making the decision on whether to suspend them less straightforward. They include cancer therapy programs and requests for help in international nuclear licensing procedures.

They also include waste management projects that the US - backed by France, Australia and other countries - want cut because nuclear waste from reactors can be reprocessed into weapons-grade material, the diplomats said.