DAMASCUS, Syria — Protesters set fire to the ruling Baath Party’s headquarters and other government buildings in the southern city of Dara’a on Sunday, as protesters rallied and clashed with the police for a third straight day, witnesses said.

Police officers fired live ammunition into the crowds, killing at least one and wounding scores of others, witnesses said. But the Syrian president, Bashar al-Assad, also made some conciliatory gestures in an apparent attempt to stop the cycle of public anger that has fueled uprisings in other Arab countries in the past three months.

Syria, a police state known for its brutal suppression of any public protests, seemed immune to the wave of uprisings sweeping the Arab world until the past week, when demonstrations took place in several cities. The southern town of Dara’a, where citizens were outraged by the arrest of more than a dozen schoolchildren, has seen the largest protests by far. Thousands took to the streets on Sunday, as they have for several days now.

Mr. Assad sent a delegation to offer condolences to the families of those killed in the clashes in Dara’a, including the deputy foreign minister, Faisal Mekdad, and Tamer al-Hajeh, the minister of local administration.