Human rights group Amnesty International said on Friday at least 55 people are believed to have been killed since protests erupted in and around the southern Syrian city of Deraa a week ago.
"Security forces again opened fire on protesters in al-Sanamayn and carried out arrests in Damascus, according to reports on Friday, a day after the authorities pledged to investigate the violence," Amnesty said in a statement.
Protests spread across Syria on Friday, challenging the rule of the Assad family after their forces killed dozens of demonstrators in the south.
In the southern city of Deraa, which has been in revolt for a week, gunfire and tear gas scattered a crowd of thousands after people lit a fire under a statue of late president Hafez al-Assad, whose son Bashar has ruled since his death in 2000.
Al Jazeera aired comments by a man who said security forces had killed 20 people on Friday in the nearby town of Sanamein.
In the Mouadamieh district of Damascus, security forces killed three people after a crowd confronted a procession of cars driven by supporters of President Bashsar al-Assad, residents said.
Meanwhile, the Syrian information minister said the situation in the country is calm, al-Arabiya television reported.
"The situation is completely calm in all parts of the country, the television station quoted Information Minister Muhsin Bilal as saying.
It was not clear when he was speaking.
The United States also weighed in on the situation in Syria, calling on the Syrian government to stop violence against demonstrators and the arrests of human rights activists, White House spokesman Jay Carney said on Friday.
"We strongly condemn the Syrian government's attempts to repress and intimidate demonstrators," he told reporters.
In Hama, in the center of the country, where the elder Assad put down an Islamist revolt in 1982 at a cost of many thousands of lives, residents said people streamed through the streets after weekly prayers chanting "Freedom is ringing out!" -- a slogan heard in uprisings sweeping the rest of the Arab world.
The same chant had earlier marked funeral processions in Deraa for some of the at least 37 people killed on Wednesday, when security agents attacked pro-democracy groups at a mosque. In all, 44 deaths have been reported in the past week in Deraa.
Security men, on alert across the country during weekly prayers at mosques, quickly stifled a small demonstration in the capital Damascus. They hauled away dozens among a crowd of some 200 who chanted their support for people of Deraa.
In Tel, near Damascus, about 1,000 people rallied and chanted slogans calling relatives of Assad "thieves".

Deraa violence

In Deraa itself, a bastion of the Sunni majority which resents the power and wealth amassed by the Alawite elite around Assad, a Reuters correspondent saw thousands rally unchallenged until the sound of heavy gunfire sent them running for cover.
Unrest in Deraa came to a head this week after police detained more than a dozen schoolchildren for writing graffiti against the government. In Damascus, a couple of protests by a few dozen people shouting slogans were broken up last week.
Among the targets of the crowd's anger on Friday was Maher al-Assad, a brother of the president and head of the Republican Guard, a special security force, and Rami Makhlouf, a cousin who runs big businesses and is accused by Washington of corruption.
Allied with Shi'ite, non-Arab Iran against the Western powers and neighboring Israel, Assad's Syria sits at the heart of a complex web of conflict in the Middle East.
His anti-Israel stance has protected him against some of the criticism aimed, for example, at Egypt's deposed leader Hosni Mubarak, who defended a peace treaty with the Jewish state.
Demonstrators in Deraa turned that hostility to Israel against the government on Friday, highlighting the use of force against them and the failure of the Assads to take back the Golan Heights.
"Maher, you coward!" they chanted. "Send your troops to liberate the Golan!"
In Deraa, before the Friday midday prayers which are the high point of social interaction in much of the Arab world, a procession of cars coursed through the streets honking horns and raising pictures of the president. There were also pro-Assad congregations in other parts of the city.
Minarets in Deraa echoed throughout the morning with the calls of imams to the faithful to attend funerals of some of the civilians killed, most of them when security forces fired on demonstrators in the mainly Sunni Muslim city on Wednesday.
A Facebook page called Syrian Revolution called on people to gather on the "Friday of Dignity" after prayers, "in all mosques, in all provinces, in the biggest squares".
Bashar al-Assad promised on Thursday to look into granting Syrians greater freedoms in an attempt to defuse the outbreak of popular demands for political freedoms and an end to corruption.
He also pledged to look at ending an emergency law in place since 1963 and made an offer of large public pay rises.
Syrian security forces pulled out on Thursday from the mosque where several people were killed. People later converged on the mosque to celebrate its "liberation", setting off fireworks and honking car horns.