More than 8,000 people have been killed in Syria since the uprising began a year ago, and many more injured .Fearing ill-treatment at official hospitals, demonstrators have sought help at underground clinics. One Damascus surgeon tells his story.

I was at home, looking out of the window, watching a demonstration, when I saw a car being driven very fast. Two men from the security forces leaned out and started shooting randomly at the demonstrators - shooting to kill.

The demonstrators were doing nothing, just shouting for freedom. There were a lot of dead and injured people on the ground.

The demonstrators ran inside a mosque, and some began shouting over the loud-speakers: "Stop killing us! We don't have guns, we are peaceful! We have injured men, we have to treat them!" They asked for doctors, nurses, medical supplies and blood bags.

I took some medical equipment and went to the mosque, using side streets to avoid snipers. Inside it was terrible. There were no medical supplies, not many doctors, too many injured people… People were dying in front of my eyes.

Image caption Many of the injured in Homs have also been treated in makeshift clinics

We asked them to go to the hospital, but they said: 'We can't - yesterday people were taken to the hospitals and now we don't know what has happened to them.' Their friends had told them that going to hospital is basically a death sentence. The security forces might arrest you, torture you, or even kill you.

My colleague was working at a military hospital in Damascus. He said a lot of injured people came in - some with only minor injuries - and all of them were killed.

I asked him, 'Are you sure about that?' He said, 'Yes I'm sure. All of them were dead.'

At the [civilian] government hospitals, they didn't kill anyone, but they were beating them. One of the injured men I treated myself had a fracture in his hip bone where he'd been shot, and I asked him: 'Why is this? A bullet does not make this kind of injury.'

How it began "It started with one doctor then it became two, then six, then 12. This was the nucleus of our organisation. Every doctor has his branches, and the branch has its own branches, so sometimes we are working in the same organisation but we don't all know each other. That way if someone gets caught and they force him to name names, not too many other doctors will be arrested too. We set up field hospitals in basements, farms, abandoned building, even cars. At the beginning of the uprising, we used to go out to the areas where the demonstrations take place the day before, and get a field hospital ready. But after Ramadan it became more complicated, because there were demonstrations every day and killings was every day."

He said someone in the security forces jumped on his leg at the hospital, and that's how it was broken. He managed to escape, and came to us.

There are two kinds of injuries that we treat - from bullets, and from torture or beating. The most dangerous ones are the injuries from gunfire. We can treat injuries to the legs, the hands, the shoulders. But a gunshot in the chest or abdomen - we can't do anything. The patients die.

We need morphine for those in acute pain, but we can't get it. Sometimes we try to get it smuggled in through, but it's risky. A lot of activists have been killed smuggling medicine.

Every few weeks, we hear that the security forces have come into a field hospital and taken all the supplies or arrested a doctor.

They have their own spies, even among us. You can't trust everyone - sometimes the man who is carrying an injured demonstrator to a field hospital is a spy.

One of our doctors was arrested and the security forces showed him a video where he was helping demonstrators in the field hospital. So the video was made by a spy, who pretended he was with us. He had also given information and details about our field hospital's location.

In the circumstances we are operating in, when we can't do anything for the patients, it's very disappointing.

We feel hopeless, because when you see that someone is dying between your hands, and the government hospital is just five minutes away from the location where you are… that hurts your heart. It hurts your humanity.

Find out more The doctor spoke to the BBC World Service programme Outlook More from Outlook More from BBC World Service

The only people who can get treated are those who support of the government. It's inhumane.

In the beginning I was counting the number of people who I wasn't able to save, but I'm not counting them anymore. It is written in your brain, in your head… The memories, the images, the blood, the shouting.

It is very dangerous. In the beginning we were afraid to work. But we need to know inside ourselves, in our hearts, that we are human. Our role, as doctors, is to treat the injured, whoever they are.

If a doctor is caught treating demonstrators, they might arrest him or even kill him. Two days ago a doctor in Homs was murdered with a knife through his neck. And five days ago, another doctor was also murdered with a knife, along with his wife and three children.

So far I believe 54 medical staff have been killed, including nurses, doctors and medical students.

What motivates me? My honour, my duty as a doctor.

When we graduated from medical school we took the Hippocratic oath. And the way that I was raised, my religion, everything. I'm part of the human race, and I need to honour this oath, as a doctor and as a human."

The doctor, who is part of the Damascus Doctors Coordinate, spoke to theBBC World ServiceprogrammeOutlook.