According to Aljazeera report,the United States and Russia came up short on Sunday in attempts to finalize a ceasefire deal in Syria, as US President Barack Obama said “grave differences” remained and fighting on the ground continued.

Russia and the US have been striving for weeks to secure a ceasefire between Syrian President Bashar al-Assad’s government and moderate rebels that would expand humanitarian access to hundreds of thousands of civilians caught in the crossfire.

The strategy has hinged on an unlikely US-Russian militarily partnership against “extremist groups” operating in Syria. But beyond the Islamic State in Iraq and the Levant (ISIL) and al-Qaeda, Moscow and Washington have conflicting views about who fits in that category.

Obama said on Sunday on the sidelines of the G20 economic summit in Hangzhou China.

“We’re not there yet,”

“It’s premature for us to say that there is a clear path forward, but there is the possibility at least for us to make some progress on that front.”

Negotiations between US Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov were set to continue in China on Monday.

Russia and the US have backed opposing sides in the conflict.