UNITED NATIONS — The United Nations’ top human rights official called on the Muslim world to denounce the “monstrous” crimes of the extremist group that seeks to establish an Islamic state in Iraq and Syria, calling its actions both a violation of international law and Islamic tenets.

Zeid Ra’ad Al Hussein, a member of the Jordanian royal family and the first Muslim to be named high commissioner for human rights, on Tuesday urged the Security Council to back efforts to overturn the Islamic State’s “ideology of violence.”

His speech was equally a message to the Muslim world.

“It is also disturbing how few to nonexistent have been the public demonstrations of anger in the Arab and Muslims worlds over the crimes being perpetrated in Iraq — notwithstanding the clear condemnation by many Arab and Islamic governments,” Mr. Al Hussein said.

Citing the opinion of Muslim clerics, he said the group had violated Shariah in many instances, through conversions, the reintroduction of slavery and the killing of civilians. He said Islam also prohibited the killing of diplomats and emissaries, which could be extended to journalists and aid workers.