Addressing the thousands of New Yorkers who gathered in front of the United Nations yesterday to protest the Iranian regime, Natan Sharansky likened the country’s leaders to the Soviet communists.

The former Soviet dissident urged the crowd to stand up for human rights and “defeat this evil empire again.”

Chanting “Stop Iran now,” rally-goers listened to speeches by a Holocaust survivor, Elie Wiesel; a former Canadian minister of justice, Irwin Cotler; the speaker of Israel’s Knesset Dalia Itzik, and other Jewish leaders and human rights activists.

Senator Clinton and Governor Palin had been scheduled to speak at the event, but Mrs. Clinton pulled out after the Republican vice presidential nominee said she would attend. Protest organizers then rescinded Mrs. Palin’s invitation and those of other politicians, saying they wanted to keep the event nonpartisan.

A number of rally attendees said they were disappointed that Mrs. Palin was not speaking, and some waved placards bearing her name.

Frimah Laub — a Holocaust survivor holding a homemade cardboard sign that read, “Where is Sarah?” — said the Alaska governor should have attended the rally. “Sarah should have been here to show the Democrats that she really has a backbone,” she said.

A Brooklyn resident who said she plans to vote for Senator McCain, Leah Nemetsky, said she suspected that Mrs. Clinton pulled out of the protest because she did not want to share the spotlight with Mrs. Palin. “She knew Sarah Palin would outshine her,” Ms. Nemetsky said.

Despite some protesters’ praise for Mrs. Palin, the speakers at the rally avoided partisanship and focused their comments on President Ahmadinejad’s pledge to annihilate the Jewish state.

“The Holocaust did not begin with the gas chambers; it began with words,” Mr. Cotler said.

Mr. Wiesel urged the Iranian president, who is in New York for the annual U.N. General Assembly session, to “go home and stay there.” In a jab at Columbia University, which hosted Mr. Ahmadinejad last fall, Mr. Wiesel said the president’s place was not at universities or the United Nations “but in Holland in a U.N. prison cell.”

Among the hundreds of students who attended to protest the Iranian regime was Joelle Keypour, an Iranian-Canadian who was draped in an Israeli flag.

“My mom fled from the revolution in 1979, and I’m here to support her and my family and all oppressed Iranians,” Ms. Keypour, who along with 130 other students traveled 10 hours on a bus from Toronto to attend the event, said.

Across the street from the rally, a group of Iranian-Americans calling themselves the Ad-hoc Committee Against Ahmadinejad held large signs documenting the execution of women and political prisoners in Iran. The committee is planning to hold a rally today at 11 a.m. outside the United Nations, and Mr. Ahmadinejad will address the U.N. General Assembly later in the day.