The UN Security Council's inability to pass a resolution on Syria has encouraged the government to step up its assault on the opposition and launch an "indiscriminate attack" on civilians in the city of Homs, the UN human rights chief has said.
"The failure of the Security Council to agree on firm collective action appears to have emboldened the Syrian
government to launch an all-out assault in an effort to crush dissent with overwhelming force," Navi Pillay, the High Commissioner for Human Rights told the UN General Assembly on Monday.
Pillay added that crimes against humanity have likely been committed in the bloody crackdown on dissidents.
"The nature and scale of abuses committed by Syrian forces indicate that crimes against humanity are likely to have been committed since March 2011," she said, speaking of the crackdown in which an estimated 6,000 people have died in less than a year.
Activists say President Bashar al-Assad's forces have killed at least 500 people in Homs just since February 4 when they began attacking the central city with a barrage of tank shells, mortar rounds and rocket-propelled grenades.
In-depth coverage of escalating violence across Syria
The assault on Homs began on the same day Russia and China vetoed a second UN Security Council resolution on Syria.
That move prompted the Arab League to ask the United Nations for a joint Arab-UN peacekeeping mission to the strife-torn country.
Syria has however ignored the latest Arab initiative to end the bloodshed, with tanks and artillery continuing to pound Homs.
"The risk of a humanitarian crisis throughout Syria is rising," warned Pillay in the UN address.
Earlier on Monday, Russia's foreign minister made it clear that Moscow would not support a plan to send United Nations peacekeepers to Syria unless there was a halt to violence by both government forces and their armed opponents.
Sergei Lavrov said on Monday that Russia was studying the proposal for a joint UN-Arab peacekeeping force in Syria, announced on Sunday at an Arab League meeting in Cairo, and wanted more details.
But his remarks suggested his country, which has veto power at the UN Security Council, would use the proposal to
underscore its own argument that the government's armed opponents are no less of an obstacle to peace than Assad's forces.
UN peacekeeping missions "need to first have a peace to support," Lavrov told a news conference after talks with Sheikh Abdullah bin Zayed al-Nahyan, foreign minister of the United Arab Emirates Foreign Minister.
"In other words, it is necessary to agree to something like a ceasefire, but the tragedy is that the armed groups that are
confronting the forces of the regime are not subordinate to anyone and are not under control," Lavrov said in Moscow.
Russia joined China in a double veto to block a UN Security Council resolution supporting an Arab League call for Assad to quit, provoking strong criticism from the Western and Arab sates that supported the draft.
On Sunday, the Arab League called on the UN Security Council to create a joint peacekeeping force for Syria and urged Arab states to sever all diplomatic contact with Assad's government.
Syria immediately rejected the move, spelled out in a resolution adopted by the league's foreign ministers meeting in Cairo.
Arab foreign ministers also decided to halt all diplomatic dealings with representatives of the Syrian government, though they did not demand the expulsion of Syrian ambassadors from member states.
Saud Al-Faisal, Saudi foreign minister, conveyed the 22-nation league's deep frustration with Syria, telling delegates that it was no longer appropriate to stand by and watch the bloodshed.
"Until when will we remain spectators?'' he said. The bloodshed in Syria, "is a disgrace for us as Muslims and Arabs to accept".
The Arab League suspended an observer mission in Syria last month, and on Sunday that Elaraby accepted the resignation of Sudanese General Mohammed al-Dabi, who led the troubled mission.
Elaraby recommended appointing former Jordanian foreign minister and UN envoy to Libya Abdel Ilah al-Khatib as Dabi's replacement.