“They surrounded us from different sides with their tanks, machine guns and warplanes that also participated in the assault,” said Mohamed, 25, a resident reached by telephone as he fled for the Turkish border.

“Shots were falling like the rain,” he said.

The battle in this small northern town, just 12 miles from the border with Turkey, may not prove decisive for either side in an uprising that has stretched across Syria since it began in mid-March. There was no way to know exactly how many people died on either side.

The fight represents a potentially dangerous turning point, experts said, one where the government appears to have abandoned all pretense of trying to offer democratic change to calm an angry public, and where at least part of the opposition has abandoned peaceful tactics to take up arms against the state.

The case of Jisr al-Shoughour has also ratcheted up international pressure on Syria — especially from its neighbors, who had been careful to avoid criticizing President Bashar al-Assad for fear of greater instability in the region if he were deposed.