Two protesters also were killed during clashes late Saturday in Doroud, authorities said.
He called the Iranian people "smart", "sophisticated", and "proud".
Earlier on Monday, it was reported that the number of civilians killed amid the pro-and anti-government demonstrations has grown to 10. Hundreds have been detained since then.
In stunning scenes, Iranian protesters chanted "Death to the dictator!" as they tore down posters of supreme leader Ayatollah Ali Khamenei, who holds absolute authority in Iran. Demonstrators have been voicing their anger over Iran's stagnant economy and alleged government corruption since Thursday in Mashhad.
He added that "after the confrontation of the past days it is all the more important for all sides to refrain from violent action".
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. However, he said that Iran would counter "a small minority group" of rioters and outlaws seeking to exploit the protests and use them to harm Iran.
Israeli Prime Minister Benjamin Netanyahu wished Iranian protesters "success" fighting for their freedom, in a video released on YouTube on Monday.
'US Mainland in Our Nuclear Strike Range' - Kim Jong
Mullen's warning comes as tensions continue to increase between North Korea and the worldwide community. The U.S. "should accurately be aware that this is not a threat but a reality".
After initial silence, state media has shown footage of unrest, focusing on young men violently targeting banks and vehicles, an attack on a town hall in Tehran, and images of a man burning the Iranian flag. Israeli decision-makers see a nuclear-armed Iran as an existential threat.
According to social media reports and a video verified by BBC, at least two protesters in the western Iran town of Dorud were shot, but their conditions were not reported.
State TV said armed demonstrators had tried and failed to seize police and military bases. The firebrand Republican has not minced any words while criticising the Iran nuclear deal and has even refused to certify it, while dumping even more sanctions on the Islamic nation. According to the State TV reports on January 1, 2018. It was unclear where the others occurred.
On the other side, Ahmadinejad's supporters organized protests against the Green Movement's supporters and chanted against the so-called foreign interference in Iran's domestic affairs by the US and western countries.
"I do not know whether yesterday's shooting was done by rally participants or the police and this issue is being investigated", Khademi was quoted by ILNA as saying. He said the cause of death wasn't immediately known, though authorities later described one of the deaths as the result of a personal dispute.
From the capital, Tehran, to Kermanshah in the west and the holy city of Qom in the north, Iranians defied police to vent frustration against a government that allows limited space for political dissent.
Regional governor Mostafa Samali told Fars that only one person was killed in an incident unrelated to the protests, and the suspected shooter had been arrested.