Turkey watches as Syria's rebellion encroaches

You can hear gunfire cracking over the hills of Syria just across the border these days and, through binoculars, you can see soldiers stationed on the tops of buildings.

The Syrian civil war has moved very close to Turkey. Pro-Assad forces control all the big towns, many of the villages, and most of the roads in Idlib province, which borders Turkey.

That is what has driven thousands more refugees into Turkish territory, bringing tales of extraordinary cruelty by the soldiers and Shabiha pro-government militias, and of arduous journeys through the hills and forests, carrying children, the elderly and wounded on their backs.

Having battered rebellious districts of Homs into submission last month, the Syrian government directed its armour and helicopter gunships at Idlib, which had been largely controlled by the Free Syrian Army since the end of last year.

The insurgents have been forced to retreat again, unable to defend themselves against tanks and helicopter gunships. But they have not given up.

"The Syrian army isn't occupying our towns and villages," explains Captain Ammar al-Wawi, a former intelligence officer who is now one of the chief commanders of the Free Syrian Army on the Turkish side of the border, "they are just destroying them".

Much of the hilly countryside in Idlib is still roamed by bands of armed activists, who, even if not under the direct command of the Free Syrian Army, usually describe themselves as being a part of it.

Desperately short of weapons, they hope that pro-Assad forces will eventually be distracted by uprisings elsewhere in Syria, and pull back enough to allow the opposition to re-take some of their original positions, and re-open supply lines from Turkey.

With many of their former strongholds in government hands, the border country in Turkey is now the scene of frantic activity by activists to keep the insurgency alive.

In some frontier villages, young men carry plastic grocery bags of food and other supplies over the border every day to sustain those FSA bases just inside Syria, using well-worn smuggling routes.

Syrians living in western countries or the Gulf have flown in to help organise supply efforts, or to raise funds.

There are also volunteer networks to look after the wounded. Those with serious conditions are usually moved to Turkish hospitals; the Turkish authorities say they are treating around 50 Syrian patients.

They are guarded by Turkish police. Those being treated include one man whose legs have been blown off below the knee by a tank round, and another man with blast injuries from a landmine.

Less severe casualties are looked after in makeshift clinics, hidden behind the walls of residential buildings in the provincial capital Antakya. They store and sort donations of medicines there, in the hope of being able to send them to the fighters over the border.

The Turkish government has built seven camps to accommodate the refugees, who now number more than 16,000. There is an efficient system for feeding and sheltering them, but it is a cramped and often stressful existence.

Most of them are housed in tents provided by the Turkish Red Crescent, which have not been the ideal shelter during a very cold and wet winter.

There is a constant fear of informers from the Syrian mukhabarat, the domestic intelligence agency. A near-riot broke out at the Boynuyogan camp on Sunday when inmates thought they had identified two infiltrators; the Turkish security forces quickly detained them and drove them out of the camp.

Most of the young men in the camps say they want to help the FSA, and some do go back across the border to join the insurgents. These efforts are not always successful.

At Boynuyogan we heard of 14 young men who went across last week, but were betrayed by people in a village where they were staying. Government forces moved in at night, we were told, and shelled the shed where they were sleeping, killing them all.

Other men volunteer to help bring refugees into Turkey, another dangerous task. People often have to move away from the roads for the last several kilometres of their journey to the border. We were shown video shot on their phones of women and children being helped to scramble over trees that had been felled across surging rivers.

But for all this activity the revolution along this part of the Turkish-Syrian border appears to be in stalemate. Hopes of international intervention on their behalf are fading among the opposition groups, and being replaced by a grim and increasingly militant resolve to grind the Assad regime down on their own.

At Capt al-Wawi's home there is a sense of order and military efficiency you do not often see in the Syrian opposition. He commands the Ababeel Battalion, based around Aleppo. It is one of more than 30 inside Syria that are loosely under the command of the Free Syrian Army.

The Turkish government puts most of the defecting soldiers who cross the border in a special camp near the town of Apaydin. They include the man most widely recognised as the FSA's commander, Colonel Riad al-Asaad.

It is tightly guarded and off-limits to journalists, for the safety of its inmates, insist the Turkish authorities.

It is also because Turkey wants to keep control of any insurgency based on its territory. Despite strong verbal support for the opposition, the government has so far blocked supplies of weapons reaching the FSA, and barred armed attacks, from Turkish soil.

Capt al-Wawi has chosen to live outside the security of the camp, to give himself more freedom to organise actions in Syria. But he is careful to acknowledge Riad al-Asaad's authority. This is a revolution, he says. Even generals coming over to join the Turkish-based opposition - eight have defected so far - must accept the new hierarchy, roughly based on how early soldiers defect.

He also has a warning for sympathetic countries. This is already a civil war, he says, and those fighting President Assad are becoming angrier and more militant.

Without more help, that anger could be directed not just against China and Russia for backing President Assad, but also against those who failed to back his opponents.