The United Nations accused Syria's government and rebels of hindering aid access, suggesting both sides could be violating UN Security Council demands that emergency relief reach civilians caught in the crossfire of the three-year civil war.
A month after the 15-member council achieved rare unity to unanimously approve a resolution demanding rapid, safe and unhindered aid access, including across borders, UN chief Ban Ki-moon said the situation "remains extremely challenging".
In Ban's first report to the council on the implementation of the February 22 resolution, he said 175,000 people remain besieged by government forces and 45,000 people trapped by opposition groups in several areas.
No new ceasefires were brokered to gain access to these areas and there were breaches of existing ceasefires, Ban said.
Some 9.3 million people in Syria need humanitarian assistance, Ban said, while another 2.6 million have fled the three-year civil war, sparked in March 2011 by a revolt against President Bashar al-Assad.
"Humanitarian access in Syria remains extremely challenging for humanitarian organizations," Ban said. "Delivering life-saving items, in particular, medicines, remains difficult. And the assistance reaching people continues to fall far short of what is required to cover even their basic needs."
The Security Council expressed "its intent to take further steps in the case of non-compliance" with the resolution. But diplomats say Russia is unlikely to agree to any action, such as sanctions, if Syria's government was found to be at fault.
The Security Council is due to discuss Ban's report on Friday, diplomats said.
Russia, supported by China, has shielded its ally Syria on the Security Council during the three-year war. They had previously vetoed three resolutions that would have condemned Syria's government and threatened it with possible sanctions.
In the 13-page report, Ban said there were significant challenges to the delivery of aid in Syria.
"Including: the need for multiple requests for approval of inter-agency convoys, which often go unanswered; the Government's lack of internal communication of approvals to those on the ground, resulting in denial of access or delays at checkpoints; and continued insecurity," Ban said.
"Increased fighting between armed opposition groups, including between Free Syrian Army (FSA)-aligned and ISIS (Islamic State of Iraq), has complicated the delivery of assistance including the cutting off of key access routes in some locations in the northern parts of the country," he said.
The opposition Syrian Observatory for Human Rights says more than 136,000 people have been killed during the conflict.
Ban said that as the violence intensified, more people were slipping out of the reach of humanitarian help.
"Around 3.5 million people are now estimated to be in need of assistance in hard-to-reach areas, an increase of 1 million since the beginning of 2014," he said.
No walking away
Ban reported that in the past month, "there were continued reports of artillery shelling and air strikes, including the use of barrel bombs, by government forces. Car bombings and suicide attacks, including against civilian objects, resulted in civilian deaths and injury during the reporting period."
He said many of the car bombs and suicide attacks were claimed by Islamist extremist groups the Islamic State of Iraq and Jabhat Al-Nusra, while "government-controlled cities and towns, including Damascus, were subject to mortar attacks by armed opposition groups".
"Reported daily death tolls were on average exceeding 200 people, including civilians, inside Syria," Ban said.
Following the adoption of the council resolution, he said the Syrian government had established a working group with the United Nations and the Syrian Arab Red Crescent to discuss ways to increase aid access.
The United Nations presented a list of 258 hard-to-reach areas to the working group, but many of those locations have yet to be accessed with assistance, Ban said.
"Limited aid was delivered to a number of hard-to-reach areas in the reporting period for the first time in several months," he said. "However, there were several instances in which aid convoys either could not proceed or were prevented from carrying essential items, such as medicines."
"Since the adoption of the resolution, medical supplies have been removed by government officials from inter-agency convoys to (Homs and rural Damascus) ... which would have assisted around 201,000 people," he said.
Ban said aid supplies were allowed to be brought into Syria through government-controlled crossings with Lebanon and Jordan. The Yarubiya crossing with Iraq, however, remained closed because the Syrian government "objected to the raising of the Democratic Union Party (PYD) Kurdish flag there," he noted.
Following repeated requests from the United Nations, the Syrian government allowed UN aid trucks to cross from Turkey for the first time during the conflict.
But when the United Nations asked for more cross-border access, particularly from Jordan and Turkey, Syria's government "restated its position that any border crossing can be opened as long as it is a 'legal' official crossing point and will not compromise the sovereignty of the Government of Syria."
UN aid chief Valerie Amos had urged the Security Council to act to increase humanitarian access in Syria. Amos has repeatedly expressed frustration that violence and red tape have slowed aid deliveries to a trickle.
"Syria is now the biggest humanitarian and peace and security crisis facing the world," Ban said. "The United Nations does not have the option of walking away from Syria."