UNITED NATIONS — More than 70 humanitarian organizations are accusing the United Nations of allowing the Syrian government to manipulate relief efforts and deprive thousands in besieged areas of help.

The aid groups working in Syria and neighboring Jordan, Lebanon and Turkey announced in a letter to the U.N. humanitarian office in Turkey, obtained Thursday by The Associated Press, that they are suspending participation in an information-sharing program aimed at improving aid delivery.

This is “a first step in response to the political influence of the Syrian government and the inaction of U.N. agencies and other humanitarian actors based in Damascus,” the letter said.

Britain’s Guardian newspaper reported last week that the U.N. has awarded contracts worth tens of millions of dollars to people closely associated with President Bashar Assad including groups set up by his wife, Asma, and cousin, Rami Makhlouf, who is one of Syria’s most prominent and wealthy businessmen.