Security forces in Syria have fired on anti-regime protesters, killing six and wounding scores in the southern town of Daraa.
Hundreds of people had gathered at the Omari mosque, the focus of the rallies since Friday, to prevent police from storming it.
"Security forces fired live bullets and teargas on protestors" staging a sit-in near the Omari mosque in Daraa, an activist at the scene said.
"They cut off electricity and the firing started," he added.
Those killed included Ali Ghassab al-Mahamid, a doctor from a prominent Daraa family who went to the Omari mosque in the city's old quarter to help victims of the attack, which occurred just after midnight, said the residents, declining to be named.
Syria, which is still under a 1963 emergency law banning demonstrations, has witnessed a string of small but unprecedented protests demanding the end of the ruling Assad regime for one week now.
Daraa, a town about 60 miles south of Damascus and home to large tribal families, has been the focal point of the rallies, the latest in a string of uprisings against long-running autocratic regimes in the Arab world.
The demonstrations also spilled into the nearby towns of Jassem and Noa, where eyewitnesses said more than 2,000 protesters gathered for a rally before being quickly dispersed by security forces.
Six people have been killed earlier in a security crackdown on the Daraa demonstrations, including an 11-year-old boy who died on Monday after inhaling tear gas the day before.
Syrian authorities have also detained writer Louai Hussein, one day after he posted a petition online demanding the right to freedom of expression, a London-based rights group reported.
Hussein, 51, is a former political prisoner who was jailed from 1984 to 1991 over his activism with the communist party in Syria, the Syrian Observatory for Human Rights said.
Organisations including Human Rights Watch have accused the Syrian authorities of detaining dozens of activists at a rally outside the interior ministry last week.
The crackdown on protesters also earned a harsh rebuke on Tuesday from the European Union, which condemned the authorities' handling of the rallies as "unacceptable."
EU foreign policy chief Catherine Ashton said in a statement that the 27-nation bloc "strongly condemns the violent repression, including through the use of live ammunition, of peaceful protests in various locations across Syria."