Despite accusations by Syrian authorities, Islamists did not instigate and are not leading the unrest that has rocked the country for a month, although they are partners in the protests, analysts say.
"They are certainly present but they are not directing it. This popular uprising does not depend on the old political parties," said Rime Allaf, a researcher on Syria at London-based think-tank Chatham House.
Around 220 people have been killed by security forces or plainclothes police since the emergence of the protest movement in mid-March, according to human rights watchdog Amnesty International.
"The Muslim Brotherhood has lost much of its influence since (the 1982 massacre in) Hama, and especially after they allied themselves with former vice president Abdel Halim Khaddam," Allaf said.
Khaddam was second in command during the rule of Hafez al-Assad -- father of the the current President Bashar al-Assad -- before breaking with the regime in 2006.
The Muslim Brotherhood was born in Syria in 1945, but banned there since the Baath party took power in 1963.
The Brotherhood, which is fervently Sunni, considered the regime "apostate" because of its secular characteristics and its leadership by the minority Alawite Shiite sect.
The Brotherhood multiplied attacks against the regime from 1976 to 1982, before being crushed in its stronghold of Hama in the 1982 massacre of 20,000. Membership in the Brotherhood is still punishable by death.
In February 2006, the Syrian Muslim Brotherhood leader Ali Sadreddine Bayanouni formed an opposition front with Khaddam.
"The Muslim Brotherhood is indeed still a political force and its popular base is concentrated in major Sunni urban areas such as Hama, Aleppo and Homs," said Faysal Itani of London-based risk assessment group Exclusive Analysis.
"However, it is neither well organised nor does it have any formal structures," he said.
"As it stands, the most significant role it can play in the uprising is by declaring support for protests and having its sympathisers participate in them," said Itani, deputy head of Middle East and North Africa forecasting.
"Its ability to conduct a protracted insurgency as seen in the late 1970s and early 1980s is low, if not non-existent."
He said that could change if the group were provided weapons and training by Sunnis in neighbouring Iraq, or disaffected soldiers and officers from the largely Sunni military.
Since the beginning of the protest movement on March 15, Assad's regime has blamed "armed criminal gangs" for the violence.
On Monday, when the protests amplified, Syria's interior ministry promised to put down a "rebellion armed by Salafist groups," a reference to a fundamentalist Muslim movement.
Thomas Pierret, an associate at Berlin's Zentrum Moderner Orient research institute, said however there was "nothing to suggest that the Salafists have played a significant role in the events, although it is likely that they participated in events as they are a component of the Sunni population."
The uprising was "a largely spontaneous and therefore very fragmented movement," Pierret said, adding whenever leadership has emerged it has been largely local, from religious figures, tribal chieftains and liberal professionals or from youths.
Pierrot said the religious Salafist movement, born in the early 20th century in Syria, has widespread influence in society, but does not have institutions because of official repression. The last major Salafist figure was Abdel Kader al-Arnaout, who died in 2004.
But the US-led invasion of Iraq in 2003 gave rise to a more radical offshoot of "jihadi" Salafists, who believe in "holy war" and made their mark through three operations, including a September 2006 attack against the US embassy in Damascus. Some analysts disagree about the role of the Brotherhood in the Syrian protest movement.
"In a society repressed by the security services there have to be determined elements -- that is to say politicised -- to stir it all, like the Muslim Brotherhood, communists and others," said Bassma Kodmani, a Syrian-born researcher at the Arab Reform Initiative, which is based in Paris and Beirut.
"These are the backbone" of the protests," she added.