The UN is deeply concerned about the deteriorating humanitarian conditions faced by 13.4 million internally displaced Syrians, it said in a statement.
"Some of the most vulnerable Syrians are those who are in the north-west of the country, where there are now 3.4 million people in need. More than 90 per cent of those [people] are assessed by the UN to be in extreme or catastrophic need, particularly the 2.7 million internally displaced men, women and children. Most of the displaced are living in over 1,000 camps and informal settlements on the Syrian-Turkish border," spokesperson for the UN Secretary-General, Stéphane Dujarric, said in a press briefing held on Monday.
For such people, access to UN services can only be obtained through the UN Security Council-authorised cross-border operation, where the Bab Al-Hawa crossing remains the UN's last entry point for assistance.
Dujarric explained that the aid that is being sent by the UN team from Turkey into the north-west of Syria is reaching 2.4 million Syrians on a monthly basis; with around 1,000 trucks of aid crossing the border each month. "A total of 979 trucks crossed in May alone," he said.
He stressed that Bab Al-Hawa is the last lifeline preventing a humanitarian catastrophe for millions of people in Syria and noted that there remains no alternative to delivering aid at this scale and with this scope.
"This is why the Secretary-General has said a large-scale cross-border response for an additional 12 months remains essential to save lives," he said.
Syria has been ravaged by a civil war since early 2011, when the Assad regime cracked down on pro-democracy protesters.
Half a million people have been killed and more than 13 million displaced, according to UN estimates.