The US and Russia have offered starkly differing assessments of the situation in Syria at the UN Security Council session, underscoring the global body's inability to unite around a strategy to end the civil war in the Arab country.
Whereas Hillary Clinton, the US secretary of state, decried Syrian President Bashar al-Assad for "murdering his own people," Sergey Lavrov, the Russian foreign minister, accused the US and other countries of encouraging terrorism.
Clinton appealed on Wednesday for the "paralysed" council to make a new attempt to reach an accord on taking measures over the conflict.
"The atrocities mount while the Security Council remains paralysed and I would urge that we try once again to find a path forward," Clinton said.
The Russian foreign minister, however, showed no sign of changing tack and said violence by the government and opposition had to be condemned.
"A significant share of the responsibility for the continuing bloodshed rests upon the states that instigate the opponents of Bashar al-Assad to reject a ceasefire and dialogue and demand an unconditional capitulation of the regime," Lavrov said.
Mulling intervention force
Meanwhile, Arab ministers have met with UN-Arab League envoy Lakhdar Brahimi on the sidelines of the UN General Assembly, and Tunisia's President Moncef Marzouki said later his country could support an Arab peacekeeping force in Syria.
"A peacekeeping operation by Arab nations is something we could well imagine," Marzouki told AFP, calling President Bashar al-Assad "a bloodthirsty dictator."
"We have really pushed for a peaceful solution, but if it is necessary, it must be an Arab peacekeeping force, yes."
On Tuesday, the emir of Qatar called at the UN General Assembly for an Arab intervention in Syria.
Arab League secretary general Nabil al-Arabi told reporters he did not believe the emir intended a "fighting force."
But he told a Security Council meeting on the Middle East that the council must support Brahimi by making its resolutions on Syria "binding on all parties".
Russia and China have used their powers as permanent members of the council three times to block resolutions which could have led to potential sanctions.
Western diplomats say they do not expect Russia, Syria's main ally, to weaken its defence of Assad. But they say China, which does not have the same strategic interests, may now be feeling pressure from Arab and other nations over its position.
Laurent Fabius, the French foreign minister, has said it was "shocking" that the council had been unable to act in the 18 months since the uprising against Assad started.
"As the international community, we must be united to stop the violence and help initiate a process of political transition. We must find a common response. We owe it to the people," Guido Westerwelle, the German foreign minister, said.
None of the ministers have specifically mentioned Russia or China, but diplomats said the targets are clear and that the campaign is also being waged on a wider stage.
In-depth coverage of escalating violence across Syria
David Cameron, the British prime minister, told the UN General Assembly that the tens of thousands of deaths in Syria conflict had become a "terrible stain" on the reputation of the UN.
"The future for Syria is a future without Assad," Cameron told the 193-member assembly, highlighting a report this week that outlined the horror suffered by children who have seen killings and been tortured in the conflict.
"The blood of these young children is a terrible stain on the reputation of this United Nations," Cameron said.
"And in particular, a stain on those who have failed to stand up to these atrocities and in some cases aided and abetted Assad's reign of terror."
China's Foreign Minister Yang Jiechi was more defensive.
"China has faithfully fulfilled its obligations and acted as a positive force in seeking a political solution to the issue," he said.
"China is ready to join the rest of the international community in an unremitting effort to resolve the Syrian issue in a just, peaceful and appropriate way."