Faced with a simmering fury in the country, Iran’s leaders on Wednesday abruptly softened their stance toward street protests that are believed to have left hundreds of civilians dead last month, the most lethal crackdown since the 1979 revolution.

The change, led by Supreme Leader Ayatollah Ali Khamenei and President Hassan Rouhani, signaled that the hierarchy was scrambling to manage resentment worsened by a brutal suppression of protests throughout the country after gasoline prices were increased by at least 50 percent without warning on Nov. 15.

The authorities shut down the internet for 10 days and deployed security forces to quell the unrest, including through the use of firearms. Unofficial accountings have said between 180 and 450 people were killed — figures that the government has disputed as baseless or speculative. But it has not provided a confirmed total.

Mr. Khamenei, who previously had denounced the protesters as rioters, thugs, monarchists and enemy agents, called on the judiciary to show “Islamic mercy” and draw a distinction between people who had demonstrated against the gasoline prices and those who had pillaged and burned public property.

In what appeared to be another significant concession, Mr. Khamenei said he had approved the term “martyr” to be used for citizens who were “caught in crossfire and riots and died without playing any role in instigating them,” according to the official Islamic Republic News Agency. Martyr is among the highest honors bestowed posthumously on loyal servants of the Islamic Republic.

Mr. Rouhani announced the formation of a committee, consisting of the ministers of interior and justice and his legal adviser, to investigate the unrest and propose compensation for Iranians who lost loved ones or suffered financial loss.

Political analysts said the measures suggested that Mr. Khamenei may now believe he miscalculated the effects of a tough response on angry citizens increasingly weary of economic deprivations.

“They are adding that money, paying money to calm them down,” said Rasool Nafisi, an Iranian academic and publisher in the United States. He called it “a very important step, because Khamenei’s view is that you should not yield to protests.”

Expressions of anger in Iran over the crackdown have proliferated, particularly since the internet blackout was eased starting last week. Some have drawn an analogy between the shooting of protesters and a deadly crackdown in 1978 by government forces that helped precipitate the downfall of Shah Mohammed Reza Pahlavi a year later.