In a major blow to humanitarian efforts in Syria, the United Nations Security Council failed to renew the authorization of the delivery of humanitarian aid to the rebel-held northwest of the country.

The authorization allowed for the delivery of aid through the Bab al-Hawa border crossing, which expired on Monday. The council failed to adopt two rival resolutions that would have extended the deliveries, leaving millions of people in dire need without vital assistance.

The Bab al-Hawa crossing has been crucial in providing aid to the northwestern province of Idlib, home to about 4.1 million people. Many of them have been displaced from their homes during the 12-year civil war, and rely on aid that comes through this crossing.

The devastating earthquake that hit the region in February further exacerbated the need for humanitarian assistance, with over 4,500 deaths and widespread damage to homes.

While Syrian President Bashar Assad opened two additional crossing points from Turkey to increase aid flow, the majority of U.N. aid is delivered through Bab al-Hawa. The closure of this crossing will severely limit the ability to deliver aid to those in need.

The United Nations has pre-positioned supplies in the region, but it is not enough to compensate for the loss of aid through Bab al-Hawa. The failure to renew authorization was caused by a veto from Russia, which has consistently pushed for aid to be delivered across front lines within Syria, effectively giving the Syrian government control over the shipments.

A compromise resolution, supported by 13 out of the 15 council members, was vetoed by Russia. A rival Russian resolution also failed to gain sufficient support. The United States, United Kingdom, and France voted against the resolution, while 10 countries abstained. The situation has raised concerns about the ability to provide essential aid to millions of people in need in northwestern Syria.

U.N. Secretary-General Antonio Guterres has called on Security Council members to redouble their efforts to support the continued delivery of cross-border assistance for as long as possible.

The closure of Bab al-Hawa will have a devastating impact on the region, where hundreds of thousands of people live in tent settlements and rely on aid for survival. The international community must find a solution to ensure that these vulnerable populations receive the assistance they desperately need.