A United Nations official says he is appalled by the efforts of some political and religious leaders to use the attack at an Orlando, Florida nightclub to fuel intolerance, fear and hatred.

Adama Dieng, the U.N. special adviser on the prevention of genocide, said in statement Friday that he was "particularly sickened to hear religious leaders commend the killings of members of the LGBT community."

Dieng also criticized calls by some politicians, without mentioning names, who blamed Islam for the attack and who are calling for Muslims to be banned from the United States.

He said "any advocacy of national, racial or religious hatred that constitutes incitement to discrimination, hostility or violence is prohibited under international human rights law as well as by the legislation of many countries."