At least five people were killed in Syria, activists said, despite an order from President Bashar Al Assad for security forces not to open fire on protesters and an offer of dialogue.
Friday's bloodshed cast a pall over the government's pledges to forge ahead with reforms in Syria, which has been gripped by two months of deadly protests.
The violent crackdown triggered fresh condemnation from Western governments, with the United States expressing renewed outrage and French Foreign Minister Alain Juppe blaming Assad for the deadly repression.
Britain summoned the Syrian ambassador in coordination with other European nations, warning of "further measures" if it fails to stop the crackdown.
Three people were shot dead during protests in the central city of Homs and two others were killed as they emerged from the main weekly Muslim prayers at a mosque in the Qabun neighbourhood of Damascus, activists said.
A woman also died Friday of injuries sustained a few days earlier in Hara, near the southern town of Daraa, epicentre of the pro-democracy protests that erupted March 15, they added.
One of those killed on Friday was Fuad Rajab, 40, who was hit by a bullet to the head when security forces fired to break up a demonstration in the flashpoint city of Homs.
The army, which has been working alongside the security services to crush the protest movement, used batons, tear gas and water cannons to disperse demonstrators in the city of Hama further north, activists said.
But the protesters succeeded in ripping down a town hall portrait of Assad, one of them added.
Security sources also fired warning shots Friday to disperse thousands of anti-government protesters in Daraa, scene of a massive 10-day military operation that ended last week.
Amateur videos showed rallies in Ibtaa village, near Daraa, where protesters demanded a new president, and in Syria's second city Aleppo, as well as in the port city of Latakia.
Friday rallies also swept the northern, mostly Kurdish regions of Qamishli, Derbassiye and Amuda, activists said.
Several dissidents were arrested on Friday in Homs and in and around Damascus, the head of the London-based Syrian Observatory for Human Rights, Rami Abdul Rahman, said.
Among those rounded up were human rights activist Catherine Talli who was seized in the Damascus neighbourhood of Barzeh, he told AFP on Saturday.
Assad's office had reportedly promised that security forces would not open fire on demonstrators as the government announced plans to launch a "national dialogue."
Louai Hussein, a writer and leading activist, said in a message posted on his Facebook page, that senior presidential adviser Bouthaina Shaaban had "told me during a telephone conversation that strict presidential orders were given not to fire on the demonstrators."
"All of those who violate these orders will assume full responsibility," he quoted Shaaban as saying.
Information Minister Adnan Mahmud said that the army started on Friday to pull out of the coastal province of Banias where it deployed in force last week.
"After having ensured a return of security, the army divisions have started a gradual withdrawal from Banias and its province," Mahmud said.
"A general national dialogue will start in the coming days in every governorate," he told reporters, adding that Assad had already met delegates from several regions.
"The president has heard their grievances and their opinions about what is going on in Syria," the minister said.
In Washington, US State Department spokesman Mark Toner said chances were narrowing for Damascus to respond to its people's demands.
"We continue to look at ways to apply pressure on the Syrian regime," Toner said, expressing "outrage" at the crackdown.
In London, Foreign Office political director Geoffrey Adams urged Syria to "stop the killing of innocent protesters immediately, and to release all political prisoners."
The French foreign minister, in an interview published Saturday by the pan-Arab newspaper Al-Hayat, said: "The use of tanks to respond to the demands of the people for more freedoms and democracy is unacceptable."
Up to 850 people have been killed and at least 8,000 arrested since the protests started in mid-March, human rights groups say. The regime has blamed the deadly violence on "armed terrorist gangs."