Iran's Supreme Leader has accused his country's enemies of meddling in recent protest rallies, as the reported death toll reached 20.
Ayatollah Ali Khamenei's website quoted him as saying enemies of Iran have used various means including money, weapons, politics and intelligence apparatuses "to create problems for the Islamic system".
The Iranian leader, who has final say on all state matters, did not name any country but said he would explain more in the near future.
This is the first time he has commented publicly since protests over inflation and economic corruption began on Thursday in Mashhad and spread to other cities.
More than 20 people, including protesters and security forces, have reportedly died in clashes and hundreds have been arrested.
Overnight clashes between protesters and security forces killed nine people, state television reported, including some rioters who tried to storm a police station to steal weapons.
The demonstrations, the largest to strike Iran since its disputed 2009 presidential election, have seen six days of unrest across the country.
Hundreds of people have been arrested and a prominent judge on Tuesday warned that some could face death penalty trials.
State TV reported that six people were killed during an attack on a police station in the town of Qahdarijan. The report said clashes were sparked by rioters who tried to steal guns from the police station.
State TV also said an 11-year-old boy and a 20-year-old man were killed in the town of Khomeinishahr, while a member of Iran's paramilitary Revolutionary Guard was killed in the town of Najafabad.
It said all three were shot with hunting rifles, which are common in the Iranian countryside.
The towns are all in Iran's central Isfahan province, 215 miles south of Tehran.
It was not immediately clear if the Revolutionary Guard member was the one reported late on Monday night by Iran's semi-official Mehr news agency.
Mehr had said an assailant using a hunting rifle killed a policeman and wounded three others in Najafabad.
Monday night saw the first fatality among Iran's security forces.
President Hassan Rouhani has acknowledged the public's anger over the Islamic Republic's flagging economy, though he and others warned that the government would not hesitate to crack down on those it considers law breakers.
None of the protest rallies have received permission from the Interior Ministry, making them illegal under Iranian law.
In Tehran alone, 450 protesters have been arrested in the last three days, the semi-official ILNA news agency reported on Tuesday. ILNA quoted Ali Asghar Nasserbakht, a security deputy governor of Tehran, as saying security forces arrested 200 protesters on Saturday, 150 on Sunday and 100 on Monday. So far, authorities have not released a nationwide figure for arrests.
The head of Tehran's Revolutionary Court reportedly warned on Tuesday that arrested protesters could potentially face death penalty cases when they come to trial.
The semi-official Tasnim news agency quoted Mousa Ghazanfarabadi as saying: "Obviously one of their charges can be Moharebeh", or waging war against God, which is a death penalty offence in Iran.
Mr Ghazanfarabadi also was quoted as saying some protesters will come to trial soon on charges of acting against national security and damaging public properties.
The protests began over Iran's economy, which has improved since the nuclear deal that saw Tehran agree to limit its enrichment of uranium in exchange for the end of some international sanctions.
Tehran now sells its oil on the global market and has signed deals to purchase tens of billions of pounds of Western aircraft.
That improvement has not reached the average Iranian. Unemployment remains high, and official inflation has crept up to 10% again.