syrian tank
A Syrian tank stationed in the city of Homs

Syrian security forces have adopted a shoot-on-sight policy to prevent refugees fleeing across the border into Turkey, according to families who have braved the journey in the past week.

Yayladagi, near the Turkish border of Syria

They describe a heavy build-up of troops and tanks slowing the flood of refugees to a trickle.

Human rights campaigners say they are investigating dozens of reports that civilians have been shot dead as they try to cross.

Their stories illustrate how President Bashar al-Assad shows no sign of easing his grip on power or heeding international calls for calm.

Wednesday brought a fresh wave of arrests as Syrian troops raided houses in a Sunni district of the besieged port of Latakia, detaining hundreds of people and taking them to a stadium at the end of a four-day tank assault to crush protests.

Activists say more than 1,800 people have died and more than 30,000 arrested since democracy demonstrations erupted across the country five months ago.

Thousands have fled to the safety of camps in Turkey, but those arriving in the past week bring harrowing tales of bravery.

Mohammed, a former policeman, arrived at the Turkish border town of Yayladagi on Sunday after surviving an ambush by security forces that killed his wife and his driver.

Cuddling his one-year-old daughter, he described how his wife and elderly father had rented a car to take them from the village home near the western city of Hama - the scene of intense bloodshed last week - to the border.

They planned to send back the car and walk the last couple of miles though the mountain frontier.

But about 15 minutes' drive from the border they were flagged down by a policeman. After checking their driver's documents, said Mohammed, he waved them on.

"When we started to drive on we saw a burnt-out car hidden in the trees and then they started shooting. They had given us permission to go but it was an ambush." The car came to an abrupt halt and Mohammed threw himself through the door, dragging his seven-month pregnant wife behind him.

She was bleeding heavily from three gunshot wounds, he added.

"She told me to go, to make sure our daughter was safe and that I wouldn't live if I tried to take her.

"It was the hardest thing. The bullets were still coming," said Mohammed. "I try to tell myself she is a martyr for Syria."

The Daily Telegraph has also learned that a man was shot and wounded on Saturday as he tried to take food across the border for families sheltering in forests on the Syrian side.

Four more people were killed as they tried to escape the brutal crackdown on Tuesday.

"They are just shooting at anyone who gets close to the border. They are going to kill everyone," said a Syrian man who has been arranging for refugees to cross.

Mousab Azzawi, of the Syrian Observatory for Human Rights, said dozens of similar reports could not be verified as researchers were unable to reach the border areas.

"People are finding it very difficult to escape now as there are many obstacles in their way and tanks and soldiers occupy many of the key strategic points along the border," he said.

Activists around the world also face threats and intimidation, added Dr Azzawi, describing how Syrian diplomats in the UK, US and several other countries were monitoring dissidents, and sending intelligence back to Syria where relatives were arrested.

"I have been told that if I return home I will face a dramatic death after torture," he said.

The UN Security Council is due to meet Thursday to discuss the latest bloodshed, which last night prompted Turkey - seen as crucial to finding a solution - to repeat its calls for an end to the violence.

"If the operations continue in Syria and the operations become a regional problem Turkey can naturally not remain indifferent," said Ahmet Davutoglu¸ Turkish Foreign Minister.