GENEVA - Many Syrian civilians will face starvation if Damascus and armed rebel groups do not allow greater access to humanitarian convoys carrying life-saving supplies, the UN envoy to the war-ravaged country said Thursday.

There “are plenty of civilians at the moment in danger of starvation,” Staffan de Mistura told reporters, following the weekly meeting of the United Nations-backed humanitarian taskforce struggling to coordinate aid deliveries across Syria.

De Mistura’s second-in-command and head of the taskforce, Jan Egeland, meanwhile said it had so far this month proved far more difficult than expected to reach people in besieged and hard-to-reach parts of Syria with aid. “Of the one million people that we have planned and have tried to reach by land in May, we’ve only so far reached 160,000,” he told reporters.

The United Nations says more than 400,000 people are living under siege in Syria, most of them in areas besieged by the regime.

In addition, more than four million people are living in so-called hard-to-reach areas that are generally near fighting and checkpoints, according to UN figures.

Since February, there have been efforts to dramatically scale up humanitarian aid access to these areas, but delivering supplies has become increasingly difficult amid a surge in violence that has left a February truce hanging by a thread.

Even areas where the UN had received full approvals to go in, “there has been infinite problems in actually reaching the places,” Egeland said.

While in other areas where the approvals were based on a number of conditions, like the besieged rebel held towns of Daraya and Douma, “we haven’t been able to reach the people at all,” he added.

Egeland said aid was also failing to reach the besieged towns of Moadamiya in rural Damascus and Al Waer, near Homs.

“I would say the situation is horrendously critical,” he added referring the crisis in the three besieged places.

“Children are so malnourished in these places that they will be dying if we are not able to reach them,” he warned.