The protests in Kermanshah, the main city in a region where an quake killed over 600 people in November, took place a day after hundreds rallied in Iran's second largest city Mashhad to protest at high prices and shout anti-government slogans.
Large numbers are reported to have turned out in Rasht, in the north, and Kermanshar, in the west, with smaller protests in Shiraz, Isfahan and Hamadan.
Police arrested 52 people in Thursday's protests, Fars quoted a judicial official as saying in Mashhad, one of the holiest places in Shi'ite Islam.
"In the beginning, the protests were peaceful and the slogans were about high prices and economic corruption", added the source.
Fars reported that protesters in Kermanshah chanted anti-government slogans such as "never mind Palestine, think about us", "death or freedom" and "political prisoners should be freed".
Similarly, Iran's revolutionary court head, Hossein Heidari was quoted by Fars as saying: "We consider a protest to be the people's right but if some people want to abuse these emotions and ride this wave, we won't wait and will confront them".
Iran protests traced to past economic mishaps
"If the security and law enforcement agencies leave the rioters to themselves, enemies will publish films and pictures in their media and say that the Islamic Republic system has lost its revolutionary base in Mashhad", IRNA quoted prominent conservative cleric Ayatollah Ahmad Alamolhoda as saying.
The arrests were for "demolishing public property and lacking a permit for the protests", Mashhad's deputy attorney general, Hassan Heydari, told Tasnim. After the 2009 election, protesters gathered in the streets to challenge what they believed was a fraudulent vote that returned hardliner Mahmoud Ahmadinejad to a new term.
President Rouhani promised that the deal he signed with world powers in 2015, which saw Iran limit its nuclear activities in return for the lifting of worldwide sanctions, would boost economic growth.
Iran's involvement in regional conflicts includes its backing for Syria's President Bashar al Assad, militarily and financially, as well as the movements Hezbollah in Lebanon and Hamas in Gaza. "It seems that there is something behind this issue that must definitely be identified", said Jahangiri.
"The hands of political groups could be seen in (Thursday's) gathering in Mashhad", said Leilaz.More news: Tim Cook required to fly only by private jet