Iranian state-run Press TV cited unnamed officials in Tehran as saying the Islamic Republic was looking to hold on to its low-enriched uranium and buying what it needed for the Tehran reactor abroad.
The report indicated that Iran will not meet terms the West said it agreed to — including transferring most of its stock of enriched uranium, the potential base for fissile warhead material. Tehran says it needs enriched uranium for nuclear fuel.
"Buying nuclear fuel from abroad does not mean Iran will stop its uranium enrichment activities inside the country," Ali Shirzadian, spokesman for Iran's Atomic Energy Organization, told Iran's official IRNA news agency.
"If the talks do not bring about Iran's desired result ... we will start to make 19.7 percent enriched uranium ourselves," Shirzadian told Reuters a few hours before the talks were due to start.
The U.S. says Iran is now one to six years away from being able to make such arms, should it choose to.
Meanwhile, the head of the U.N. nuclear agency says talks with Iran's International Atomic Energy Agency delegation were off to a"good start" in Vienna.
Mohamed El Baradei, who heads the International Atomic Energy Agency, attended the first day of talks Monday. He spoke of "quite a constructive meeting."
"We are off to a good start," Baradei said.
Even if Tehran agrees, it could still try to resist pressure to hand over most of its stock in one batch, insisting instead on sending small amounts out of the country. Iran still has enough fuel for the Tehran reactor to last until mid-2011.
Monday's Vienna talks between Tehran and the U.S., Russia and France, focused on the technical issue with huge strategic ramifications.
Progress would strengthen confidence on the part of the U.S. and five other big powers trying to persuade Iran to dispel fears about its nuclear program that this time Tehran is serious about reducing tensions and ready to build on Oct. 1 Geneva talks with six world powers.