Speaking in Tehran Friday, Mr. Ahmadinejad said Iran will not tolerate "pressure" but remains ready for negotiations.
Hours earlier, Chinese Foreign Minister Li Zhaoxing said China will play a "constructive role" in efforts to resolve Iran's nuclear standoff with the West.
Li Zhaoxing made the remark in a joint news conference in Beijing with visiting U.S. Secretary of State Condoleezza Rice.
Rice said the two sides discussed efforts at the U.N. Security Council to draft a resolution that is likely to impose sanctions on Iran for refusing to stop its uranium enrichment activity.
China and Russia have been resisting tougher measures against Iran, while urging negotiations to end the standoff.
European Union foreign ministers have expressed support for limited sanctions against Iran.
In another development, Israeli Prime Minister Ehud Olmert told reporters Thursday, during a flight from Moscow that Iran would have "a price to pay" if it does not back down from its nuclear ambitions. He did not elaborate.
Iran has ignored an August 31 U.N. deadline to suspend uranium enrichment. Iran denies Western charges that it seeks to develop nuclear weapons.
Some information for this report was provided by AFP, AP and Reuters