TEHRAN (Dispatches) – The Islamic Revolution Guards Corps (IRGC) on Monday warned rioters of "decisive” action if they try to take advantage of peaceful protests over gasoline price hikes to stir unrest and undermine Iran’s security.
Since Friday, at least 100 banks and dozens of buildings and cars have been torched by what an intelligence agency has described as trained saboteurs.
President Hassan Rouhani’s government said the gasoline price rises were intended to raise around $2.55 billion a year for extra subsidies to 18 million families - or roughly 60 million Iranians on low incomes.
They are aimed at fending off reimposed U.S. sanctions that have helped undermine the government’s promises of more jobs and investment.
"If necessary we will take decisive and revolutionary action against any continued moves to disturb the people’s peace and security,” the IRGC said in a statement.
Leader of the Islamic Revolution Ayatollah Seyyed Ali Khamenei on Sunday said Iran’s enemies were stirring up the turmoil by the help of "thugs” and "hooligans” whose main aim is to destroy public property.
Authorities said one policeman and a civilian had been killed and 1,000 rioters arrested.
"Rioters used knives and guns...A number of security agents and policemen were killed or taken hostage,” Government spokesman Ali Rabiei told a televised news conference Monday.
The rioters, he said, took police and security personnel hostage during the unrest.
The situation was "calmer" Monday. Rabiei said there were still "some minor issues" but predicted that "tomorrow and the day after we won't have any issues with regard to riots".
"There have been gatherings in some cities, in some provinces," he said.
Rabiei said the government should soon unblock internet access across the country, and estimated attendance in demonstrations has dropped by 80% compared to the day before.
Major roads have been blocked, banks torched and shops looted in the unrest since Friday.
Masked young men were seen on debris-strewn streets setting buildings ablaze in footage that has been aired on national television. The volunteer Basij force also reported looting.
Basij commander Brigadier General Gholamreza Soleimani said the United States is instigating the unrest and said "America's plot failed”.
The U.S. on Sunday expressed support for the rioters and accused Iran of using "lethal force" against demonstrators.
Iran's Foreign Ministry slammed U.S. Secretary of State Mike Pompeo after he tweeted "the United States is with you" Saturday in response to the riots.  
In a statement issued Sunday, the ministry said it was reacting to Pompeo's "expression of support... for a group of rioters in some cities of Iran and condemned such support and interventionist remarks".
"The dignified people of Iran know well that such hypocritical remarks do not carry any honest sympathy," spokesman Abbas Mousavi was quoted as saying.
The ministry also blasted Washington's "ill-intent" over its decision to reimpose sanctions.
"It's curious that the sympathizing is being done with the people who are under the pressure of America's economic terrorism," Mousavi said.
Germany also made meddling statements on Monday, with Chancellor Angela Merkel's spokeswoman Ulrike Demmer saying "it is legitimate and deserving of our respect when people courageously air their economic and political grievances, as is currently happening in Iran".
President Rouhani said Sunday, "Protesting is the people's right, but protesting is different from rioting. We should not allow insecurity in the society."
The intelligence ministry said at the weekend that it had identified those behind the unrest and that measures would be taken against them.
Forty people have been arrested in the central city of Yazd and another 180 in the southern province of Khuzestan, Iranian news agencies reported Sunday.
The IRGC arrested 150 protest "leaders" in Alborz province, said Tasnim news agency, adding they had confessed to having "received money" to torch buildings.
Many in oil-producing Iran see cheap gasoline as a fundamental right and the price hike sparked worries about a further squeeze on living costs, despite state assurances that the revenue raised would be put to assisting needy families.