United Nations: The UN human rights chief has decried Syria's escalating crackdown on civilian protesters and warned that the Security Council's failure to take action has emboldened the Syrian government to launch an all-out assault to crush dissent.

Navi Pillay on Monday expressed fears that the deliberate stirring of sectarian tensions may plunge Syria into civil war. She said there are strong indications of ongoing crimes against humanity and again appealed for President Bashar Assad's government to be referred to the International Criminal Court.

Standing before the 193-member General Assembly, Pillay said tens of thousands of people, including children, have been arrested, more than 18,000 reportedly are still arbitrarily detained, and thousands more are reported missing.

Another 25,000 people are estimated to have sought refuge in neighboring countries, and more than 70,000 are estimated to be internally displaced, she added.

The UN high commissioner for human rights said the use of torture by Syrian security forces is widespread in interrogation and detention facilities, citing information from army defectors. She called reports of sexual violence, particularly the rape of men and boys in places of detention "particularly disturbing."

The General Assembly is expected to consider a nonbinding resolution similar to the Security Council resolution that Russia and China vetoed on February 4.

The resolution backs an Arab League plan that calls for Assad to hand power to his vice President and allow creation of a unity government to clear the way for elections. There are no vetoes in the assembly, and diplomats said a vote on the Arab-sponsored resolution could take place late this week.

In her speech, Pillay deplored the ongoing assault on the central city of Homs, which reportedly has killed 300 people in the last 10 days, and said her office has received similar accounts of intensifying assaults and worsening humanitarian situations in Zabadani, Dar'a and al-Rastan.

"The risk of a humanitarian crisis throughout Syria is rising," she said.