Rights activists and residents say Syrian troops backed by armored vehicles have stormed into the central city of Homs, killing at least one person and wounding 20 others.
The witnesses said the attacks Monday included troops firing machine guns.
The clashes come as Syria holds the second day of a national dialogue on political reform. Some opposition activists and intellectuals have joined the talks, but most prominent Syrian dissidents boycotted the conference to protest President Bashar al-Assad's deadly crackdown on the opposition uprising.
During the first day of talks Sunday, a number of speakers condemned the government's security forces and its violence against protesters. But others repeated Mr. Assad's contention that foreign agitators are attempting to destabilize Syria.
Mr. Assad proposed the event last month as a gesture to appease the opposition, which has been holding regular mass protests since March to demand an end to his family's four-decade rule of the country.
Rights groups say Syrian security forces have killed at least 1,600 civilians in the crackdown, while the government blames the violence on terrorists and Islamists who it says have killed hundreds of security personnel.
The United States on Sunday accused Syria of organizing an angry, two-day demonstration outside the U.S. embassy in Damascus to protest Ambassador Robert Ford's visit to the besieged anti-government town of Hama. France lodged similar complaints Sunday after a pro-government mob damaged its Syria missions.
Ford and French Ambassador Eric Chevallier traveled to Hama Thursday and Friday to show solidarity with its residents, who have come under attack from government forces while staging some of the largest protests to date against Mr. Assad.
The visits have been interpreted as a strong diplomatic warning against escalating violence in the central city, which has been surrounded by tanks for a week.
Syria's foreign ministry called the visits “flagrant interference” in the country's internal affairs meant to undermine its stability.
