Cars were reportedly torched in Tehran after nightfall on Monday as protesters chanted anti-government slogans in defiance of an appeal for calm by president Hassan Rouhani on Sunday night when he promised more "space for criticism". State media said that armed protesters tried to over-run police stations and military bases.
According to the broadcaster, all three of the deceased were shot with hunting rifles.
It wasn't clear whether the Revolutionary Guard member was the same fatality report late Monday night by Iran's semi-official Mehr news agency.
The towns are all in Iran's central Isfahan province, some 215 miles south of Tehran.
The demonstrations, the largest to strike Iran since a disputed presidential election in 2009, have seen six days of unrest across the country and a death toll of at least 20.
Can protesters drive them out?
The state TV report 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.
The Iranian government shut down access to social media platform Instagram on Sunday, as well as a popular messaging app, which protesters used to organize.
Israel's assessment also claims that protesters are now also demonstrating against Iran's support for Syria and its backing of Lebanon's Hezbollah and Yemen's Houthi rebels, Channel 10 reported.
He tweeted yesterday: 'The great Iranian people have been repressed for many years. They are hungry for food & for freedom.
Police arrested a number of demonstrators who were trying to damage public property in the gatherings.
He warned that Iran will use its right to reciprocate the enemies' hostile moves in a way that they will regret their deeds.
Iran's intelligence ministry released a statement saying "instigators" have been identified "and will be dealt with seriously soon".
'We regret the loss of life that has occurred in the protests in Iran, and call on all concerned to refrain from violence and for global obligations on human rights to be observed, ' he said.
Rouhani, a moderate force among Iranian hardliners, came to power in 2013 promising to mend the economy and ease social tensions, but high living costs and a 12 percent unemployment rate have left many feeling that progress is too slow.
Iran's economy has improved since the nuclear deal, which saw Iran agree to limit its enrichment of uranium in exchange for the end of some global sanctions.