New York, United States - US President Barack Obama and his Russian counterpart, Vladimir Putin, jibed at each other at an annual UN meeting, alongside signs that the two leaders may be inching towards compromises on Syria's civil war.
They spoke at an opening session of the UN General Assembly that featured back-to-back speeches from so many leaders - including the presidents of Brazil, China, Iran and France - that it was dubbed "massive Monday".
Obama said Moscow's annexation of Crimea had left the country more isolated and poorer, with ever-greater numbers of Russians leaving the country.
"Imagine if, instead, Russia had engaged in true diplomacy," the US president said.
For his part, Putin pointed to the US-led invasion of Iraq and the Western-backed rebellion in Libya that contributed to "violence, poverty, and a social disaster" across the region and huge refugee flows into Europe.
They also clashed over Syria, where President Bashar al-Assad is accused of barrel bombing civilians and other atrocities in a war that has claimed about 250,000 lives since it erupted in 2011.
Putin told delegates that there was no alternative to cooperating with Damascus.
"No one but Assad's forces are truly fighting the IS and other terrorist groups in Syria," he told delegates, using an acronym for the Islamic State of Iraq and the Levant (ISIL) group that controls swaths of Syria and Iraq.
During his speech, Obama did not explicitly call for Assad's ouster and he suggested there could be a "managed transition" away from his rule - a sign that the US may be willing to see Assad stay for some period of time.
"The United States is prepared to work with any nation, including Russia and Iran, to resolve the conflict," said Obama, who spoke before Putin. "But we must recognise that there cannot be, after so much bloodshed, so much carnage, a return to the prewar status quo."
It was not all animosity. The two leaders clinked glasses containing sparkling rose wine and dined on caramelised short ribs at a lunch hosted by UN Secretary-General Ban Ki-moon.
Later, after the first face-to-face meeting between Putin and Obama in two years, a senior US official said the two sides "fundamentally disagreed" on the role that Assad will play in resolving the conflict.
"The Russians see Mr Assad as a bulwark against extremists; the Americans see Mr Assad as continuing to fan the flames of a sectarian conflict there," the official told reporters.
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In his speech, French President Francois Hollande insisted that Assad be replaced by a "transitional government".
Jordan's King Abdullah called for more international support in managing the Syrian refugee crisis and warned that the battle against violent extremism amounted to "a third world war".
Iranian President Hassan Rouhani slammed US acts in Afghanistan and Iraq, saying the Middle East "has turned into one of the world's most turbulent regions". Iran would help to fight terrorism and restore democracy to Syria and Yemen, he added.
Meanwhile, US Secretary of State John Kerry hosted talks with the foreign ministers of Britain, France, Germany, Saudi Arabia, Jordan, and Turkey to discuss Syria.
US state department spokesman John Kirby said they "discussed ideas for building renewed and credible diplomatic momentum that could bring an end to the conflict and allow Syrians to chart a peaceful future without Assad".
Russia has stepped up military deployments to Syria in recent weeks, reportedly with combat aircraft, tanks, and other gear to bolster Assad's beleaguered forces in their fight against multiple rebel groups in a complex multi-front war.
The Kremlin and the White House share concerns about ISIL but disagree on their approaches to the group that controls territory in Syria and neighbouring Iraq.
Putin says Damascus should be included in efforts to fight the group. The US rejects Assad and says ISIL can be defeated with US-led air strikes and ground forces from the region, including some 5,400 moderate Syrian rebels who are being trained by the US.
Hussein Ibish, an analyst at the Washington-based Arab Gulf States Institute think-tank, told Al Jazeera that the US faces tough options in Syria but should continue to work against both Assad and ISIL.
"The only way to effectively counter either is to counter both simultaneously, no matter how difficult that may be," Ibish said.
"Rejecting that in favour of an alliance with the Syrian dictatorship would be playing into the hands of ISIL perfectly and validating their narrative in an extremely dangerous and counterproductive manner."
Follow James Reinl on Twitter: @jamesreinl
Source: Al Jazeera