The United States is sceptical an agreement with Russia to decease violence in Syria can work but will keep pursuing it nonetheless, President Barack Obama said on Sunday as negotiators from both countries edged toward a deal. Obama, speaking on the sidelines of the Group of 20 economic summit in China, said the US and Russia still have “grave differences” about what’s needed to end Syria’s civil war and which opposition groups are legitimate targets for the US and Russian militaries. But he said “it is worth trying” to secure an agreement nonetheless, adding that negotiators were working “around the clock”. I think it’s premature for us to say there’s a clear path forward, but there’s the possibility at least for us to make some progress President Barack Obama “We’re not there yet,” Obama said. “I think it’s premature for us to say there’s a clear path forward, but there’s the possibility at least for us to make some progress.” A deal could be announced as early as Sunday by US Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov, said a senior US State Department official, adding that the two countries were close to a deal but still had to resolve some issues. The official wasn’t authorised to discuss the negotiations publicly and requested anonymity. Kerry and Lavrov have been deep in talks for weeks over a deal to boost US and Russian military cooperation to fight Islamic State (IS) and other extremists in Syria – a step Moscow has long sought. The emerging deal is expected to also include provisions to ensure aid can reach besieged areas of Syria and steps to prevent Syrian President Bashar al-Assad’s government from bombing areas where US-backed rebels are operating. US officials have said that as part of a deal, Russia would have to halt offensives by Assad’s government, something it has failed to do over months of diplomatic efforts. They said the US must get rebels to break ranks with the al-Qaeda-linked Nusra Front, a task that grew tougher after Nusra fighters last month successfully broke the siege of Aleppo, Syria’s largest city and the site of fierce recent fighting. Though negotiators have been hopeful a deal could come together while world leaders are gathered in Hangzhou for the G20, that optimism has been tempered by the failure of previous ceasefire deals to hold. The US has long been wary of increasing military coordination with Russia in Syria’s civil war because it says Russia continues striking moderate, US-backed opposition groups in a bid to prop up Assad. The US wants Russia to focus exclusively on IS and al-Qaeda-linked groups. Turkish incursion into Syria, backed by the US and likely by Russia too, could be a game changer in civil war “These are difficult negotiations,” Obama said. He added later: “If we do not get some buy-in from the Russians on reducing the violence and easing the humanitarian crisis, then it’s difficult to see how we get to the next phase.” Discussions about the intractable Syria conflict and the related fight against IS have been a major focus as world leaders gather for the G20, which brings together the world’s major economies. Obama, who met first Sunday with new British Prime Minister Theresa May, also planned to discuss Syria when he meets with Turkish President Recep Tayyip Erdogan, their first sit-down since the summer’s failed coup in Turkey. The attempted overthrow in Turkey has accelerated the deterioration in the relationship between Turkey and the United States. It led to Turkish accusations of US involvement, and those tensions have been aggravated by growing clashes between Turkish forces and US-backed Syrian Kurds. The US, meanwhile, has expressed concern about Turkey’s recent operations across its border into Syria. The Pentagon has backed the incursions, but said they should only be aimed at IS fighters. Turkey has used the operations to push back Syrian Kurds it accuses of seeking to claim more territory. The face of Islamic State is killed in apparent US strike in Syria For the US, the dispute is a reminder of its increasing entanglement in the long-standing local rivalries and conflicts exposed by Syria’s civil war. Since the failed coup, the US has been alarmed by Turkey’s diplomatic flirtations with Russia, Syrian President Assad’s patron, and apparent softening of its tone about the need for Assad to be excluded from a political transition. At the same time, the US continues to work toward an agreement with Russia to cooperate more closely in the fight against IS in Syria.