The geographical nature of Iran's ongoing anti-government protests is unique, analysts told CNBC on Tuesday.
At least 20 people have been reported killed during clashes as of Tuesday night, bringing the death toll from the unrest to 21. The deputy provincial governor of Tehran said Tuesday that police had arrested more than 450 protestors over the past three days, as authorities look to contain the widespread anti-government demonstrations that erupted last week.
"The geographical pattern of the protests is very interesting," Torbjorn Soltvedt, principal analyst for the Middle East and Northern Africa at risk consulting firm Verisk Maplecroft, told CNBC in an email Tuesday.
Protests against economic hardships and alleged corruption initially flared in Iran's second city of Mashad on Thursday. The clashes have since escalated across the country, with many protesters calling for the religious establishment to step down.
"The protests have since not only spread geographically but also broadened in scope to incorporate a wide range of popular grievances … There is no doubt now that the protests have now taken on a life of their own," Soltvedt said.
"Crucially, the protests are now firmly beyond the control of any political factions or movements."
Protests were reported to have initially flared up in Iran's second city of Mashad on Thursday.
Online video showed police in the capital Tehran firing water cannon to disperse demonstrators, in footage said to have been filmed on Sunday, Reuters reported.
State television reported Tuesday that a protestor had opened fire on police with a hunting rifle in the central city of Najafabad, killing one and wounding three others.
On Monday, the deputy governor of the western Hamadan Province told ISNA news agency that three protesters had been killed in the city of Tuyserkan on Sunday.
Videos on social media showed an intense clash in the central town of Qahderijan between security forces and protesters who were trying to occupy a police station, which was partially set ablaze.
The Iranian authorities appear to have been caught off guard by the eruption of large-scale anti-government rallies.
Nonetheless, there is little reason to suggest those taking part in the demonstrations are united by a clear and cohesive message — like those in the 2009 uprising.
"The ongoing protests, by contrast, show no well-defined demands, no leadership or organization, and are diffuse around Iran," Cliff Kupchan, the chairman of Eurasia Group, a Washington-based political consulting firm, said in a research note.
The ongoing clashes are the biggest public challenge to Iran's status quo since 2009, when a disputed presidential election prompted millions to take to the streets of the country to voice their anger.
The reformist protests — often referred to as the "Green Movement" — were ultimately crushed by the state. Political analysts have predicted Ayatollah Khamenei would use force to suppress protestors once again if it was deemed necessary.
Kupchan said that while the unrest is "admittedly unpredictable," it remains very unlikely that the clashes would result in a "revolutionary tipping point for Iran."
"But the final word here has to be and is about Iran's repressive capability. When it comes to regime survival, Khamenei calls the shots … It was enough to put down easily the 'Green Movement' in 2009, and it makes current chatter about regime instability way premature," he said.
— Reuters contributed to this report.