U.S. President Barack Obama and his Russian counterpart Vladimir Putin gave conflicting speeches at the start of the United Nations General Assembly, with the Syrian conflict at the heart of the frosty relations. Obama says the U.S. is willing to work with Russia and others to end the fighting but will not support leaving Syrian President Bashar al-Assad in power.

"The United States is prepared to work with any nation, including Russia and Iran, to resolve the conflict, but we must recognize that there cannot be, after so much bloodshed, so much carnage, a return to the post-war status quo," Obama said in his speech while Putin, on the other hand, says there's no alternative than to cooperate with Assad's forces to combat Islamic State militants.

RELATED: Putin says he's ready to work with US

"I relate to my colleagues the American and French presidents with great respect, but they aren't citizens of Syria and so shouldn't be involved in choosing the leadership of another country. It's Syria's business," Putin stated.

Obama did not explicitly call for Assad's ouster, and he suggested there could be a "managed transition" away from the Syrian president's rule, the latest sign that despite U.S. animus toward Assad, it was willing to see him stay for some period of time.

Putin told reporters Russia was pondering what more it could do to support Syrian government and Kurdish forces fighting Islamic State militants.

RELATED: US senator: We should accept 100,000 Syrian refugees

"We are mulling over what we would really do extra in order to support those who are in the battlefield, resisting and fighting with terrorists, ISIS, first of all," Putin said, ruling out deploying Russian ground troops and calling for the creation of a broader international anti-terrorist coalition. This appeal may compete with the coalition that the United States has assembled to fight Islamic State.