The February 6 earthquake that was centered in south-central Turkey killed more than 50,000 people and left hundreds of thousands homeless. The vast majority of the victims were in Turkey, but disaster also wreaked havoc in a part of Syria that is already mired in a protracted humanitarian crisis.

According to the United Nations, the quake and a series of powerful aftershocks claimed more than 4,500 lives in northwest Syria, injured thousands more and destroyed at least 10,000 buildings. This, in a part of the country that has been wracked by civil war for more than a decade.

Even before the earth shook on February 6, the U.N. estimates that of the 4.5 million people living in the region in Syria, 4.1 million people were already in need of humanitarian assistance. Most of the population wasn't getting enough to eat and close to half of the residents were living in camps for internally displaced persons.

Medecins Sans Frontieres (also known as Doctors Without Borders) physician Mego Terzian was in Somalia when the quake struck. He rushed to Turkey and is now the coordinator of relief operations for the medical charity in northwest Syria.

NPR talked to Dr. Terzian about trying to provide aid to Syria's earthquake survivors. The conversation has been edited for clarity and length.

What are the biggest challenges right now in the areas of northwest Syria hit by the quake?

I have been in several post-earthquake crises. I was in Pakistan in 2005, in Haiti in 2010, in Sichuan in China in 2008. Most of those interventions were very fluid. It was easy to communicate with the government. It was very easy to send human resources, the materials and medication in there. The particular thing in Syria is that these zones are controlled by the opposition [the armed forces opposed to the government of Bashar al-Assad in Damascus], so there is no state actor with whom you can deal.

It's very complicated. You need to negotiate the entrance of the medical personnel and medical supplies through a neighboring country [Turkey]. It takes a lot of time. Also, Syria is still in conflict. So there are still security related problems in the country. To send large numbers of people into these zones, it's problematic, even sometimes dangerous. So this is the difference now in Syria compared to the other experiences that I had personally in the past.

Explain that a bit more. Why is it so difficult to get international relief into these opposition-controlled zones around Aleppo and Idlib?

There are different problems.

First, everything has to come across the border from Turkey. Almost nothing is supplied from Damascus.

But for security reasons, the Turkish authorities are not allowing foreign organizations to freely cross the border since the region is controlled by non-state armed groups. So for the Turkish authorities, the zone is not considered safe and they prefer to not permit foreigners to cross the border in the region. Also, the government of Syria has a lot of concerns and hesitations about seeing NGOs crossing the border without having the authorization of the regime in Damascus. It is true that north of Aleppo, [dozens of] armed groups are operating under one umbrella. They have different commanders. Sometimes there is tension or hostile actions between themselves, and it causes serious security threats to the NGOs, especially foreign NGOs.

[The World Health Organization has stepped in and Terzian says he has been getting authorization for aid convoys to cross from Turkey.]

It's true that it takes some days, but NGOs like our organization and other international NGOs over the past 2 to 3 weeks have been able to send in a significant amount of materials and medical equipment. So it's a bit bureaucratic. It takes some time. But the situation in terms of supply of medication and medical materials has improved.

What's needed most right now by people in northwest Syria?

The level of destruction is much, much higher in Turkey compared to northern part of Syria. But the difference is that the camps, the existing camps for the displaced population in Syria, are overcrowded now. After the quake in a few days or even in a few hours, thousands of additional people arrived in these camps. A lot of efforts should be done to increase the capacity of these camps, to increase the water supply, to increase the number of shelters, in order to commit to these survivors of earthquake, to continue their life in dignity.

What about from a medical perspective. Are hospitals in the quake zone still standing? Are people able to get medical care?

Fortunately, the majority of the hospitals in Idlib and north of Aleppo are not damaged. There are 24 public hospitals in these two regions and according to the health authorities, the hospitals are able to continue their normal activities. Myself, I have visited around ten hospitals in the Idlib region and the north of Syria and the staff was there were continuing to work with the with great energy and motivation.

The problems are related mainly to the supplies. The supply mechanism and the supply system has been disrupted by the earthquake, and it was a problem even before the earthquake. Over the past five years, humanitarian aid to this region was in decline. Syria was a neglected crisis the past five years. Now, with the earthquake, the medical personnel in Syria, they hope to receive the attention of the international humanitarian community.

But the supply is the main concern. I visited several dialysis centers where the medical personnel say they need medical supplies in order to continue to receive patients that need dialysis. According to the health ministry in the region, there are also around 200 patients, survivors of the earthquake, who suffered traumas and now need specialized reconstructive surgery.

Are they able to get that surgery?

In the past we would send complicated patients for treatment in Turkey. Unfortunately now the border is closed for Syrian patients. We understand the reasons because the situation is chaotic as well in Turkey and very difficult. So now the new problem is that when there is a very sick patient, Syrian medical workers are obliged to take care of the patient with the available means inside Syria. And sometimes it's very difficult. For example, we have several patients with 80% of the body burned. And we need intensive care for these type of patients. So we need to find the solutions together with the Syrian medical doctors and treat them inside Syria.

What are you most concerned about in the coming weeks for people in northwest Syria?

It's still cold in this region. The most important thing is to be sure that the supply system will continue to work via Turkey. Otherwise, it will be very difficult to provide the health authorities and other relief groups to do the work in northwest Syria. I think, for us and our team, we need to be sure that the supply route is guaranteed for the coming weeks and months. It's the key factor if we want to continue to assist the population in the zone.

Dr. Mego Terzian, is a French-Lebanese physician. His first mission for MSF as an expatriate doctor was in 1999 in Sierra Leone.