Scores of demonstrators rallied at Rittenhouse Square this afternoon to protest the disputed election results in Iran that led to a landslide victory for incumbent President Mahmoud Ahmadinejad.

The demonstrators, many Iranian-born graduate students, wore the symbolic green to show support for opposition candidate Mir Huseein Moussavi and chanted slogans such as: "Where's my vote?" and "Stop the killings!"

Some wore handkerchiefs and surgical masks on their faces for fear that they or their families may suffer persecution from Iran's government.

"We don't want to get identified because if we go back we don't want to get captured," said a 25-year-old woman who gave only her first name, Arezou.

A doctoral student at Johns Hopkins University studying biomedical engineering, Arezou said her 18-year-old brother was beaten by police in Tehran for simply wearing a green wrist band.

The rally began about 5 p.m. with only a handful of people, but grew steadily in size. Two hours later, about 150 protesters were there, chanting "No more killings" and similar messages.

"We don't believe the official results are correct," said Alireza Salehi, 27, a graduate student at the University of Pennsylvania. "We see inconsistencies that make us really suspicious of the vote."

Salehi, who helped organize the demonstrations through Facebook, praised President Obama for "not meddling" in the election process because that "would make the situation harder for the people in the underground in Iran" who would be accused of being tools of foreign interventionists.

"I think it's pretty powerful when the state tries to stop people from expressing themselves and the people do it anyway," said Sam Slaughter, 29, who was attending the rally with his girlfriend, a 29-year-old who was born in Iran.

Pooya Molavi, 23, a graduate student at Penn, said many people in Iran are tired of Ahmadinejad because he has "supressed most of the freedoms we had and started a kind of dictatorship."

Molavi also said that Ahmadinejad's speeches have been embarrassing for many Iranians.

Contact staff writer Robert Moran at 215-854-5983 or bmoran@phillynews.com.