Mahmoud Ahmadinejad's remarks underscored Tehran's defiance amid the nuclear standoff and also sought to send a message that his government had not been weakened by the protest movement sparked by June's disputed presidential election. His comments came a day after the latest opposition protest by tens of thousands mourning a dissident cleric who died over the weekend.
President Barack Obama has set a rough deadline of the end of this year for Iran to respond to an offer of dialogue and show that it will allay fears of weapons development. Washington and its allies are warning of new, tougher sanctions on Iran if it doesn't respond.
The U.N.-proposed deal is the centerpiece of the West's diplomatic effort. Under the deal, Tehran would ship most of its stockpile of low-enriched uranium abroad to be processed into fuel rods, which would ease the West's fears that the material could be used to produce a nuclear weapon.
Iran, which denies it seeks to build a bomb, has balked at the deal's terms.
The international community can give Iran "as many deadlines as they want, we don't care," Ahmadinejad said in a speech to thousands of supporters in the southern city of Shiraz.
Ahmadinejad dismissed the threat of sanctions, saying Iran wants talks "under just conditions where there is mutual respect."
"We told you that we are not afraid of sanctions against us and we are not intimidated," he said, addressing the West. "If Iran wanted to make a bomb, we would be brave enough to tell you."
"This nuclear game thing is an old story, it's history now," the Iranian leader said, as the crowd cheered: "We love you, Ahmadinejad." He lashed out at Washington, vowing Iran will stand up against U.S. attempts to "dominate the Middle East."
He also shrugged off Iran's continued political turmoil since the June election, which the opposition says Ahmadinejad won by fraud. Large street protests have continued despite a fierce government crackdown. In the latest, tens of thousands turned out for the funeral of Ayatollah Hossein Ali Montazeri, who died Sunday, and chanted slogans against the country's rulers.
Ahmadinejad did not directly mention the protests. But he said the West mistakenly believed that Iran "has been weakened."
"The people of Iran and the government of Iran are 10 times stronger than last year," he said. "I want the whole world to know it's impossible for Iran to allow the United States to dominate the Middle East."
Iran says its nuclear program is intended only to generate electricity and that it has a right to proceed with uranium enrichment, which the United Nations has demanded it suspend. The process can produce low-enriched uranium used to fuel a nuclear reactor or higher enriched uranium, which is the basis for building a nuclear warhead.
Under the deal brokered by the U.N. nuclear watchdog agency last month, most of Iran's low-enriched uranium would be shipped abroad, where it would be enriched further to produce fuel rods. The rods would then be returned to Iran for use in a research reactor in Tehran, but it would not be possible to enrich them further to a high enough level to build a bomb.