By Michelle Nichols and Louis Charbonneau
UNITED NATIONS, April 23 (Reuters) - U.N. Secretary-General Ban Ki-moon demanded on Wednesday that the Security Council take action in Syria on violations of international law as he reported to the body that none of the warring parties was adhering to U.N. demands for aid access.
In his second monthly report to the 15-member council on the implementation of a resolution demanding great humanitarian aid access in Syria, Ban said "none of the parties to the conflict have adhered to the demands of the Council."
"The Security Council must take action to deal with these flagrant violations of the basic principles of international law," he wrote in the 21-page report. He did not specify what measures the council should take.
Two months after the 15-member council achieved rare unity to unanimously approve a resolution demanding rapid, safe and unhindered aid access, including across borders, Ban said the situation "remains an extremely challenging environment in which to work."
In that resolution, the Security Council expressed "its intent to take further steps in the case of non-compliance" with the resolution. But diplomats said Russia was unlikely to agree to any action, such as sanctions, if Syria's government was found to be at fault.
Ban issued a similar report last month. Earlier on Wednesday, U.N. humanitarian chief Valerie Amos told Reuters in Geneva that hopes for a political deal to end Syria's war were fading and it was getting harder every day to send aid to millions of trapped and displaced civilians.
Last month, the United States and European delegations said that Ban's reporting had shown the government was largely responsible for the lack of aid access, which the government denies. The Western powers said any problems caused by rebel groups were the work of Islamist fighters linked to al Qaeda.
The situation is getting worse, Ban said.
"Thousands of people are not getting the medical care, including life-saving medicines, that they need," he reported. "Medical supplies, including life-saving medicines and vaccines, and equipment for the wounded and the sick are commodities privileged throughout the Geneva Conventions.
"Denying these is arbitrary and unjustified, and a clear violation of international humanitarian law," he said. "Yet, medicines are routinely denied to those who need them, including tens of thousands of women, children, and elderly."
Ban said that nearly 3.5 million people were largely without access to essential goods and services due to the Syrian civil war, which is now in its fourth year.
The Security Council is due to discuss the report next week.
Russia, supported by China, has shielded its ally Syria on the Security Council during the war. They had previously vetoed three resolutions that would have condemned Syria's government and threatened it with possible sanctions.
The United Nations has asked for more cross-border access, particularly from Jordan and Turkey, to deliver aid. But Ban said cross-border aid access remains a problem.
"Requests made by the United Nations to the Syrian authorities to urgently authorize the use of additional border crossings still remain pending," he said. "The Syrian Government has consistently stated that they will only allow the use of border crossing points that are controlled by them." (Reporting by Michelle Nichols and Louis Charbonneau; Editing by Lisa Shumaker, Toni Reinhold)