At least 12 people have been killed in Iran since protests against fuel price rises erupted three days ago, officials have said, although reports suggest the number of dead is far higher.
The situation on the streets is unclear on account of a nationwide internet shutdown. But demonstrations are reportedly continuing in some cities.
The government said Monday had been “calmer”, despite “some minor issues”.
Meanwhile, the powerful Revolutionary Guards demanded an end to the unrest.
A statement said Iran’s “sworn and evil enemies” had once again attempted to “sow discord”, and that the force would “firmly deal with the continuation of any kind of insecurity or actions to disrupt the people’s calm and comfort”.
The foreign ministry also criticised the US for expressing support for the protesters.
Secretary of State Mike Pompeo tweeted that “the United States is with you”, while the White House said it condemned the lethal force and severe communications restrictions used against demonstrators.
Foreign ministry spokesman Abbas Mousavi described Mr Pompeo’s remark as “hypocritical” because Iran’s economy had been crippled by sanctions reimposed by President Donald Trump last year in an attempt to force it to negotiate a new nuclear deal with world powers.
The protests erupted on Friday after the government announced the price of petrol would be increased by 50% to 15,000 rials ($0.12; £0.09 at the unofficial market exchange rate) a litre and that drivers would be allowed to purchase only 60 litres each month before the price rose to 30,000 rials.
President Hassan Rouhani said the government was acting in the public interest, and that the money raised would be distributed to the country’s neediest citizens.
However, the decision was met with widespread anger in a country where the economy is already reeling as a result of US sanctions that have caused oil exports to collapse and the value of the rial to plummet, and sent the inflation rate soaring.