VIENNA, Austria - The United States and Europe urged Iran on Monday to use coming talks with world powers to ease international worry that it may be aiming to develop nuclear arms, but Tehran said such concerns were based on "fake evidence" concocted to cause it political and economic harm.

The statements at a 189-nation meeting looking for ways to strengthen the Nonproliferation Treaty reflected the divide over Iran's nuclear activities. The divisions threaten the success of the talks with six world powers and a separate meeting between Iran and the U.N. nuclear agency.

Iran and the six nations will hold discussions in Baghdad on May 23 to build on admittedly meager progress made last month in Istanbul, Turkey, where the parties agreed there might be enough common ground to focus on specifics in further talks. The United States, Russia, China, Britain, France, and Germany will try to secure an Iranian pledge that to curb production of higher-enriched uranium, which can be turned into fissile warhead material within months.

Before that, Iran's chief envoy to the International Atomic Energy Agency is to meet in Vienna next week with senior officials of the U.N. agency, which has long been trying to probe Tehran's atomic secrets. IAEA officials say they will use that encounter to press for renewed access to Iran's Parchin military site to look for signs of covert work on a nuclear weapons program.

Iran has denied that request and deflected bids by the IAEA to interview scientists suspected of involvement in alleged covert research and development work for nuclear arms.

Both the United States and the European Union laid out Western expectations Monday for the Baghdad meeting. They urged Iran to comply with U.N. Security Council resolutions demanding an end to uranium enrichment and other activities that Tehran says are for peaceful use but that can be turned toward weapons making.

"We remain concerned by Iran's persistent failure to comply with its nonproliferation obligations, including IAEA . . . obligations and U.N. Security Council resolutions," U.S. chief delegate Robert A. Wood said.

Beyond expecting Iran "to take urgent practical steps" at the Baghdad talks that will diminish mistrust in its nuclear aims, Wood said the onus was on Tehran "to cooperate fully with the verification efforts of the IAEA."

The EU also urged Iran to compromise at both the Baghdad and Vienna meetings. In a statement to the Vienna conference, EU delegate Gyoergyi Margit Martin Zanathy urged Iran to heed Security Council demands and "fully cooperate with the agency, in order to clarify all outstanding issues, in particular those which give rise to deep concerns about possible military dimensions to its nuclear program."

Iranian delegate Ali Asghar Soltanieh, however, dismissed talk of alleged secret nuclear weapons-related work as based on "unreliable and fake evidence" - and turned the tables. He demanded compensation for the resulting "political and economic damages" suffered by Iran - shorthand for sanctions that are isolating his country and most recently threatening its main cash cow, oil exports.