VIENNA, Austria — First Iran resumed work at one of its nuclear facilities despite warnings from the West. Then came news that the new president brought in one of the most hard-line elements in the Islamic regime to head talks with Europeans over its atomic program.

The moves this week were the latest signs that Iran has grown more willing to defy the West since hard-liner Mahmoud Ahmadinejad was elected president in June, replacing Mohammad Khatami, a reformer.

Three days after his inauguration, Ahmadinejad said yesterday he will submit new proposals in negotiations over his country's nuclear program but denounced a European offer of aid as an "insult."

He spoke as the U.N. nuclear agency tried to resolve the crisis without referring Tehran to the Security Council. The International Atomic Energy Agency's 35-nation board, meeting in Vienna, was considering a new warning to Iran to suspend its atomic activities.

Fresh areas of concern emerged yesterday.

An exiled dissident said Iran recently produced 4,000 centrifuges capable of enriching uranium to weapons grade. Alireza Jafarzadeh, who helped uncover details of Iran's program in 2002 that fueled U.S. suspicions the country was trying to build a nuclear bomb, told The Associated Press the centrifuges are ready to be installed at the nuclear facility in Natanz.

In Tehran, Iran announced it has improved the range and accuracy of its Shahab-3 missile. It said the weapon can strike targets up to 1,200 miles away nearly dead-on — a statement sure to unnerve Western officials who fear the regime one day will be able to fit such missiles with nuclear warheads. Such a missile could strike Israel.

Ahmadinejad spoke yesterday with U.N. Secretary-General Kofi Annan and said Iran was willing to continue the negotiations with the Europeans.

But Ahmadinejad has appointed Ali Larijani, a former Republican Guard commander and close ally of Iran's supreme leader, as the new top negotiator, Ali Agha Mohammadi, a spokesman of Iran's Supreme National Security Council, told The Associated Press.

President Bush welcomed Ahmadinejad's willingness to continue negotiations but said he was "deeply suspicious" of Iran.

"Iranians are getting a message, that it's not just the United States that's worried about their nuclear programs, but the Europeans are serious in calling the Iranians to account and negotiating," he said at his Texas ranch.

Bush said that if Iran does not cooperate, United Nations sanctions are "a potential consequence."

However, diplomats said there was little stomach for reporting Tehran to the Security Council, in part out of fears that such a move — the International Atomic Energy Agency's last resort — might inflame support within Iran for the regime's nuclear ambitions.

Envoys from some nations whose own nuclear activities have come under scrutiny, such as Brazil and Argentina, also appeared reluctant to subject Iran to measures that could be applied to their programs one day.

The IAEA's board of governors is expected to issue a resolution by tomorrow urging Tehran to suspend its nuclear activities.