Even as the UN declares the escalation of the humanitarian crisis inside Syria, new evidence indicates that it has given way to the Assad regime’s pressure, limiting any assistance to the displaced and needy.

The UN recently declared that 12.2 million Syrians — almost 60% of the pre-war population — are in need. However, Colum Lynch of Foreign Policy reports that only a small fraction of those still in the country are being helped.

In part, the assistance has been hindered by security issues and the advance of the Islamic State in northern and eastern Syria. However, the greatest barrier has been the Assad regime’s ban on access to insurgent-held areas.

In October 2013, the UN Security Council issued a statement calling on all parties to grant relief agencies and private aid groups “safe and unhindered access” to all Syrians. Last July, after months of wrangling, the Council passed the binding Resolution 2165, that authorized UN relief workers to move aid across Syria’s borders without the permission of Damascus.

However, the steps have had little effect: the UN High Commissioner for Refugees, the World Health Organization, and the World Food Program have all held out against the calls from private charities and foreign government to challenge the regime’s restrictions.

The outcome is that the UN has been outstripped by the private groups still operating inside Syria. Mercy Corps has sent 688 trucks with more than 17,000 metric tons of food, shelter, and hygiene and winter supplies into Syria since July, 70% more than the assistance delivered by 422 UN trucks in the same period. In two week, the Turkish Red Crescent sent 297 trucks into the country, compared to 207 UN trucks in four months.

Elizabeth Hoff of the World Health Organization responds that the comparison is unfair, as the WHO’s primary role is coordination of the effort by private agencies. Meanwhile, up to 32% of WHO assistance has reached insurgent-held territory, even though the regime routinely blocks lifesaving surgical supplies and trauma equipment because they can be used to heal wounded insurgents.

Hoff also cites the vaccination of more than 2.7 million children against polio, with no cases of the disease reported in a year.

However, Hoff acknowledges that the achievement is overshadowed by the difficulties. Two weeks ago, the WHO said that 1 million people have been wounded in the conflict and that diseases are spreading amid the shortages and blocking of supplies by the regime.