Tens of thousands of Syrian protesters shouted for President Bashar Assad's death in a dramatic escalation of their rage and frustration.
The crowd defied bullets and rooftop snipers after more than a week of intensified military assaults on rebellious cities.
Security forces killed at least 14 protesters, according to human rights groups.
Calls for Mr Assad's execution yesterday were a stark sign of how much the protest movement has changed since it erupted in March seeking minor reforms. The protests grew dramatically over the five months that followed, driven in part by anger over the government's bloody crackdown in which rights groups say at least 1,700 civilians have been killed.
Security forces broke up protests quickly around the capital Damascus, and elsewhere, firing bullets and tear gas.
US Secretary of State Hillary Clinton urged countries to stop buying Syrian oil and gas or selling the regime weapons.