Damascus: Troops opened fire at protesters in cities across Syria and anti-government crowds clashed in the capital's historic old city.

The once-unimaginable scenario posed the biggest challenge in decades to Syria's iron-fisted rule. Protesters wept over the bloodied bodies of slain comrades and massive crowds chanted anti-government slogans, and then fled as gunfire erupted.

Witnesses said that security forces shot 15 people in at least six cities and villages, including a suburb of the capital, Damascus. Their accounts could not be independently confirmed.

The regime of President Bashar Assad, an ally of Iran and supporter of militant groups around the region, had seemed immune from the Middle East's three-month wave of popular uprising.

His security forces, which have long silenced the slightest signs of dissent, quickly snuffed out smaller attempts at protests last month.

The Assads' leadership centered on members of their Alawi minority sect, a branch of Shiite Islam in this mainly Sunni nation has built their rule by mixing draconian repression with increasing economic freedom, maintaining the loyalty of the wealthy Sunni merchant class in the prosperous cities of Damascus and Aleppo.

Bashar Assad now faces the same dilemma confronted by the leaders of Tunisia, Egypt, Yemen and Bahrain ratchet up violence or offer concessions. A day earlier, his government seemed to test the latter track, offering to consider lifting draconian emergency laws and promising increased pay and benefits for state workers.