Syrian forces shot dead 16 people on Friday when they fired on protesters demanding the removal of President Bashar al-Assad, activists said, and European powers said Damascus should face tougher sanctions for the violence.
Tens of thousands of people rallied across the country, defying Mr. al-Assad's military crackdown and ignoring a pledge that his tycoon cousin Rami Makhlouf, a symbol of corruption, would renounce his business empire and channel his wealth to charity.
The worst bloodshed was in Homs, where activists said eight protesters were killed and state television said a policeman was killed by gunmen. One person was also reported killed in the northern commercial hub of Aleppo, the first protester to die there since unrest erupted in the south of the country in March.
Friday Muslim prayers have provided a platform for the biggest protests in the three-month uprising, inspired by revolts that have overthrown the leaders of Egypt and Tunisia and challenged autocrats across the Arab world.
Activists said tens of thousands of people protested in the southern province of Deraa where the revolt against Mr. al-Assad's rule began, as well as in the Kurdish east, the city of Hama north of Damascus, and suburbs of the capital itself.
Two northern towns were also encircled by army units, residents said, five days after the military retook the rebellious town of Jisr al-Shughour and sent thousands of refugees streaming across the nearby border into Turkey.
Syrian rights groups say 1,300 civilians and more than 300 soldiers and police have been killed since the protests broke out in March against 41 years of rule by the al-Assad family, and 10,000 people have been detained.
Authorities blame the violence on armed groups and Islamists, backed by foreign powers. Syria has barred most international journalists, making it difficult to verify accounts from activists and officials.
Mr. al-Assad has responded to the unrest with a mix of military repression and political gestures aimed at placating protesters.
On Thursday state media said Mr. Makhlouf was quitting business and handing proceeds to charity. He controls a string of businesses, including Syria's largest mobile phone operator, duty- free shops, an oil concession, an airline company and hotel, construction concerns, and shares in at least one bank.
He has been subject to U.S. sanctions since 2007 for what Washington calls public corruption, as well as EU sanctions imposed in May. He has repeatedly maintained that he was a legitimate businessman whose firms employ thousands of Syrians.
Activists said Mr. Makhlouf's step by itself would not curb the momentum of protests. They said Mr. al-Assad, who has only spoken twice in public since the uprising started, was expected to address the country soon and might unveil further measures.
The President faces international condemnation over the violence, and has seen the first signs of cracks in his security forces after a clash in Jisr al-Shughour earlier this month in which the government said 120 security personnel were killed.
There have been no mass desertions from the military, but the loyalty of Sunni Muslim conscripts might waver if the crackdown on mainly Sunni protesters continues.
Mr. Assad's family and many military commanders are members of the Alawite sect, an offshoot of Shiite Islam.
U.S. Secretary of State Hillary Clinton spoke with Russian Foreign Minister Sergei Lavrov, trying to break a deadlock over a UN Security Council resolution condemning Syria's crackdown.
Their discussion focused on "how the U.S. and Russia can work together to make sure that we can get to a UN Security Council resolution," a State Department spokeswoman said.
Russia and China dislike the idea of any Security Council judgment on Syria and have played little role in discussions on a draft resolution to condemn Syrian bloodshed against protesters.
The United States is not sponsoring the UN resolution but has made clear it supports the European draft in condemning the Syrian crackdown. The resolution would not impose sanctions.
Turkish Foreign Minister Ahmet Davutoglu held talks with a Syrian envoy on Thursday in which he called on Damascus to end the violent crackdown and pass democratic reforms.
Turkish officials said the number of refugees who had crossed over from Syria had reached 9,600, and another 10,000 were sheltering by the border just inside Syria.