The U.S is pushing for more safe passages for U.N. humanitarian aid across the Turkish border into northwestern Syria as the death toll from two devastating earthquakes climbs to over 20,000.

The roads along the only United Nations authorized border crossing known as Bab al-Hawa were badly damaged in the immediate aftermath of Monday’s quake and the first U.N. aid convoy did not reach Syria until Thursday afternoon. 

U.S. officials are calling for a U.N. Security Council Resolution immediately mandating the use of any and all access points for U.N. delivery of urgent supplies to the survivors, a U.N. official with knowledge of the negotiations in the security council told NBC News.

The U.S. move comes in answer to U.N. Secretary General António Guterres’s call for member countries to explore all possible avenues to get aid and personnel into the rebel-held area still reeling from civil war. 

In 2014, U.N. humanitarian convoys were able to access northwestern Syria through four different access points along the borders of Turkey, Iraq and Jordan.

But U.N. Security Council approval of the safe passages has dwindled in the face of growing opposition by Russia and China, which say the crossings are a violation of Syria’s sovereignty. Now only one U.N.-mandated corridor across the Turkish border remains open. 

A U.S.-supported resolution to again expand U.N. humanitarian access to Syria is likely to meet resistance from Russia, which remains an ally of Syrian regime leader Bashar al Assad. As a permanent member of the Security Council, Russia can block the measure from passing. 

“We’re going to continue to make the case, countries around the world are going to continue to make the case,” State Department spokesperson Ned Price told reporters Thursday. “And we certainly hope that Russia and all those who would stand in the way are hearing and seeing these just heartbreaking images from Syria today.”

Guterres also weighed in Thursday, telling reporters that this is a moment for unity not division.

“I would be of course very happy if the Security Council could reach a consensus to allow for more crossings to be used. “We must put people first.”

In meetings Thursday with aid organizations, the U.S. Ambassador to the United Nations Linda Thomas-Greenfield voiced U.S. support for the additional cross-border access points into Syria, according to a readout released by the U.S. Mission, to allow for the delivery of life-saving assistance.

Both nations are still reeling from a magnitude-7.8 earthquake that struck Turkey and neighboring Syria in the early hours Monday, qualifying as “major” on the official magnitude scale. Hours later, a 7.6-magnitude earthquake struck nearby.

More than 17,130 people have died in Turkey, according to the country’s disaster management agency. In Syria, over 3,800 people have been killed, according to officials there.