US Secretary of State Antony Blinken on Monday called for "unhindered" cross-border access to get humanitarian aid into Syria, calling it "more important than ever."
Chairing a meeting of the UN Security Council, Blinken said that it is "clear" that the needs of Syrians are not going to be met by the Assad regime.
"We must ensure Syrians get the aid they need," he said, adding: "The most efficient method is through border crossings ... There is no good reason [why] crossings remain closed today."
The top US diplomat demanded reauthorization of the closed borders of al-Yaroubiya (bordering Iraq) and Bab al-Salam (bordering Turkey), while keeping open Bab al-Hawa (bordering Turkey), currently the only UN-authorized humanitarian border crossing in Syria.
Turning to the March 21 regime attack on al-Atareb hospital, in Aleppo, northwestern Syria, which killed six patients and injured five staffers, Blinken said: "The coordinates had been shared with the UN, meaning the regime knew exactly where it was."
That day an additional Russian airstrike on the al-Bab border crossing with Turkey killed one civilian and injured two others.
Malnutrition in Syria
The UN delivers 1,000 trucks of cross-border aid to northwestern Syria through the Turkish border every month, but the aid effort is not "big enough," UN humanitarian aid chief Mark Lowcock told the Security Council.
More than 75% of the civilians in northwestern Syria, near the Syrian border, rely on UN aid, he said, but malnutrition persists.
He also said the al-Atareb hospital attack was "obviously deliberate."
For her part, UNICEF Executive Director Henrietta Fore underlined that across Syria, "nearly 90% of children require humanitarian assistance."
"3.2 million inside Syria and neighboring countries are out-of-school," Fore said. "In the northeast, more than 37,000 children are languishing in the al-Hol and al-Roj camps. Over 800 children are in detention centers and prisons."
She urged the council to "renew the resolution on cross-border assistance" and "spare no effort to reach an agreement on accessing children through cross-line operations to reach Idlib Governorate and other parts of the northwest."
Syria has been mired in a vicious civil war since early 2011, when the Assad regime cracked down on pro-democracy protests.
Hundreds of thousands of people have been killed since and more than 10 million displaced, according to UN figures.