The gunfire began at dawn on Friday in the town of al-Haffa on Syria’s Mediterranean coast.

At first, Wala, a 29-year-old resident of the town, leaped off her bed to the corner of the room in her first-floor apartment, flattening herself as the rat-a-tat of gunshots sounded outside her bedroom window.

When the commotion grew louder, she said, she crept to the window and peeled back the curtain. Outside, dozens of people were fleeing down the road, many in their pajamas, as four men in forest green uniforms chased them. Then, the uniformed men opened fire. Within seconds, four of the fleeing people crumpled to the ground.

“I couldn’t believe what I was seeing. I was terrified, terrified,” said Wala, who asked to be identified only by her first name for fear of retribution.

The attack in her town was part of the unrest that has shaken Syria’s coast over the last four days and has killed more than 1,000 people, the war monitoring group Syrian Observatory for Human Rights said early Sunday. It was the bloodiest outbreak of violence since rebels ousted the longtime dictator, Bashar al-Assad, in early December, then sought to assert their rule over a country fractured by nearly 14 years of civil war.

The violence broke out on Thursday when armed men loyal to Mr. al-Assad ambushed government security forces in Latakia Province, where al-Haffa is located. The ambush set off days of clashes between Assad loyalists and government forces.