Security Council led to the closure  of a U.N.-operated border crossing.

That crossing was the gateway that  supplied vital humanitarian aid  

to rebel-held parts of Northwest  Syria. The Syrian regime now says  

all deliveries will be coordinated  through Damascus and not the U.N.

But with this closure, more  than four million Syrians,  

most of whom are internally displaced, have  lost access to crucial humanitarian aid.

John Yang has more.

JOHN YANG: In a tent city in Northwest Syria,  an entire generation born into war, children who  

have only known life in the narrow lanes of this  camp and who learn to live with the bare minimum.

At the Atalrama (ph) camp, Khaled  Ahmed Hajj feeds his children what  

little he can. They dip bread in oil  and thyme, the six of them eating from  

a single small plate. They have not had  meat, fruit or vegetables for months.

KHALED AHMED HAJJ, Syrian Camp Resident  (through translator): There are no job  

opportunities for us to work. There's nothing.  Even bread and thyme, we can barely buy.  

My children are malnourished. My baby  needs food, milk, fruits, and protein.

JOHN YANG: Hajj says the closure of the  U.N.-operated border crossing at Bab al-Hawa  

on the Turkish border will block aid to his  camp. That, he says, amounts to a death sentence.

KHALED AHMED HAJJ (through translator): The  closure of the crossing will cause us to suffocate  

and starve to death. The camps depend only on U.N.  aid, and closing the crossing means killing us.

JOHN YANG: Next door, Mohammad Hasram tries  to cool his tent with water. It's over  

100 degrees on most summer days.  His youngest child can't bear it.

MOHAMMAD HASRAM, Syrian Camp Resident  (through translator): There's little  

water here. We use some of it  to cool the tent. Look at this  

dilapidated tent and other conditions.  The picture speaks louder than words.

JOHN YANG: Hasram came here after fleeing  Homs. Once known as the capital of the Syrian  

revolution, Homs has long been reduced to rubble  by the regime of Syrian dictator Bashar al-Assad.

Today, Hasram faces another  battle, keeping his children alive.

MOHAMMAD HASRAM (through translator): No one  looks at our situation and no one helps. We  

depend on U.N. aid. We used to get some  aid, but now it's completely cut off. If  

it continues to be stopped, life here  will stop. This is a food war on us.

JOHN YANG: The Bab al-Hawa crossing was  the last remaining humanitarian corridor  

between Turkey and the rebel-held Idlib province.

It closed earlier this month after Russia  vetoed a U.N. Security Council resolution,  

a move that angered many Syrians in the region.

ABDUL KAFI AL-HAMDO, Air Worker: Syrian  regime and Russians have used the food  

weapon for years against civilians. We  want to say for the whole world that you  

shouldn't wait until seeing people  dying out of hunger, out of lack of  

food and any humanitarian assistance. People in  Northwest Syria have been suffering for years.

JOHN YANG: Now the Syrian regime  wants to control aid delivery into  

these rebel-held territories through Damascus.

Charles Lister is a senior fellow and  director of the Syria and Countering  

Terrorism and Extremism Programs  at the Middle East Institute.

CHARLES LISTER, Middle East Institute: The Syrian  regime, who have spent 12 years besieging, gassing  

and killing hundreds of thousands of Syrians, now  gets to claim to the international community that  

it's willing to provide humanitarian access,  it is willing to open a border crossing.

The rate of humanitarian aid  provision into Northwestern  

Syria will unquestionably collapse significantly.

JOHN YANG: Lister said an average of  12,000 aid trucks had passed through  

the U.N. crossing each year. But  on the Assad-controlled routes,  

since 2021, only a total of 152 trucks have  delivered, an average of only 74 a year.

CHARLES LISTER: The regime would in most cases  simply refuse to allow the aid in at all. And  

all across Syria over the past 12 years, there  have been towns and cities where people have  

been eating grass, have been eating mud,  in desperation because they have no aid.

On the few occasions in those historical cases  where the regime did allow small amounts of aid  

in, they were then in the practice whereby  the Syrian regime would -- for example,  

they put shards of glass inside shipments of  flour. They put bird feces inside baby formula.

JOHN YANG: Health officials say the crossing's  closure will have a devastating effect on the  

health care system. It's already crippled by  February's twin earthquakes that destroyed  

medical facilities, killed medical staff and  damaged equipment that has yet to be replaced.

Now, with the border crossing closed,  more than half of Northwest Syria's  

remaining hospitals are at risk of shutting down.

Dr. Zuhair Karat is head of  the Idlib Health Directorate.

DR. ZUHAIR KARAT, Idlib Health Directorate  (through translator): The cessation of aid  

entry will lead to great damage to  the health sector and will lead to  

the closure of these facilities. We are  heading for a major health disaster.

JOHN YANG: That would compound an  already dire humanitarian crisis. And  

until the international community  comes up with a solution,  

millions of displaced Syrians  are looking toward a grim future.

For the "PBS NewsHour," I'm John Yang.