Mahmoud Ahmadinejad takes the world stage with a speech Wednesday to the U.N. General Assembly. He appears intent on showing he has not been weakened by three months of turmoil at home, where the pro-reform opposition has staged dramatic protests claiming Ahmadinejad's victory in June presidential elections was fraudulent.

Ahmadinejad has a reason to try to present his government as strong: On Oct. 1, Iran is to enter key negotiations with the United States and other powers seeking concessions on Iran's nuclear program.

The U.S. and its allies suspect Iran is secretly pursuing a nuclear weapon, warning that Tehran already has enough enriched uranium to build a bomb. Iran denies the accusations, saying it only aims to generate electricity.

Heading into the talks, Iran has firmly rejected demands it give up uranium enrichment, a process that can produce either fuel for a nuclear reactor or a warhead. And it doesn't want the talks to focus on the nuclear issue at all. But American and European officials warn that if no progress is made in the meetings, they will push for tougher U.N. sanctions against Iran.

In New York, Ahmadinejad is likely to come under heavy pressure over the nuclear issue. And his every step will be dogged by Iranian exiles, who plan protests over his government's postelection crackdown against the opposition. Already, exiles have been lobbying New York hotels to reject events where the Iranian president is to appear.

Human Rights Watch and the International Campaign for Human Rights in Iran on Monday called on the U.N. General Assembly to appoint a special envoy to investigate and document human rights violations committed during the postelection turmoil.