The human rights group said the number of public executions is believed to have quadrupled in 2011 compared with the previous year "in what may be a strategy to spread fear among the population and to deter protests."
"As the repression of dissenters widens, the risk of further death sentences and executions cannot be excluded," the report said.
The 71-page report said hundreds of people are believed to have been sentenced to death in Iran in the past year, mainly for alleged drug offenses, and at least three juvenile offenders were among those executed -- in violation of international law prohibiting execution of those under 18 at the time of their alleged offense.
After protests called by opposition leaders Mir Hossein Mousavi and Mehdi Karroubi in February 2011, the report said, Iranian authorities have "steadily cranked up repression of dissent in law and practice, launching a wave of arrests in recent months," an Amnesty news release stated.
The crackdown, Amnesty said, "laid bare the hollowness of Iran's claims to support protests in the Middle East and North Africa."
In recent months, arrests have targeted lawyers, students, journalists, political activists and their relatives, religious and ethnic minorities, filmmakers, and people with international connections, particularly to media, Amnesty said.
In the days leading to Friday's parliamentary election, the situation has grown worse, Amnesty said.
"In Iran today you put yourself at risk if you do anything that might fall outside the increasingly narrow confines of what the authorities deem socially or politically acceptable," Ann Harrison, interim deputy director of Amnesty International's Middle East and North Africa Program, said in the news release.
"Anything from setting up a social group on the Internet, forming or joining [a non-governmental organization] or expressing your opposition to the status quo can land you in prison."