The UN Security Council on Tuesday passed a resolution extending cross-border aid to Syria by six months.
Tuesday's agreement is similar to the duration that Russia had previously demanded while other member nations had sought a full year.
Twelve of the council's 15 members — including Russia, China and the Security Council's 10 non-permanent members — voted in favour of the measure.
Britain, France and the US abstained because they said the resolution does not go far enough to help the roughly four million Syrians in need of aid.
The US ambassador to the UN, Linda Thomas-Greenfield, said Washington could not back the resolution as it expires in January, in the middle of winter, the very moment humanitarian needs are at their most dire.
"That is the weakness of today’s resolution — it requires another action from the council to confirm what should be automatic," Ms Thomas-Greenfield said in a statement.
"Syrians could be left without blankets or fuel to heat their homes in the dead of winter ... children will freeze. People will starve. Lives hang in the balance."
Ireland and Norway, which sponsored the previously vetoed resolution, circulated a new draft on Monday that provides a six-month extension of deliveries from Turkey into Syria through the Bab Al Hawa crossing until January 10 of next year.
Bab Al Hawa is the only entry into the north-west region of Syria that does not cross government-held territories.
“Over four million people in north-west Syria are in dire need of humanitarian assistance, and the UN's cross-border aid operation provides a crucial lifeline for this,” Simon Coveney, the Irish Minister for Foreign Affairs, said in a statement.
Russia vetoed a year-long extension last week and the mechanism allowing aid deliveries expired on Sunday.
“The renewal of the cross-border humanitarian mechanism is a relief. But it is precarious, expiring in the dead of winter, with no firm guarantee of renewal,” the French mission to the UN said in a tweet.
Border aid deliveries from Turkey to Syria have been occurring since 2014 in response to the 2011 humanitarian crisis sparked by President Bashar Al Assad's violent crackdown on widespread anti-government protests.