MANILA - US President Barack Obama said on Thursday it may take some months for Russia, Iran and the Syrian ruling elite to accept that there can be no end to Syria’s civil war or a political settlement while President Bashar al-Assad remains in power.

Obama said that Moscow and Tehran recognised Islamic State as a “serious threat” but Russia’s efforts in Syria were aimed at propping up Assad. “Bottom line is, I do not foresee a situation in which we can end the civil war in Syria while Assad remains in power,” he told reporters in Manila on the sidelines of the annual Asia-Pacific Economic Cooperation (APEC) summit.

“What we are doing with our coalition members is recognising that it may take some months for the Russians and the Iranians and frankly some members of the Syrian government and ruling elites within the regime to recognise the truths that I just articulated.”

Russia began air strikes in Syria at the end of September. It has always said its main target is Islamic State militants, but most of its bombs in the past hit territory held by other groups opposed to its ally Assad. Islamic State claimed responsibility for last week’s killing spree by bombers and gunmen in Paris and for the bombing of a Russian airliner over Egypt last month.

Obama added that if he could get all the parties talking on the issue, “that could create space for that pivot”. The U.S. president also said he could close the Guantanamo Bay prison in Cuba while keeping Americans safe, but acknowledged he would face tough resistance from Congress. “I will guarantee you there will be strong resistance because in the aftermath of Paris, I think there is a very strong tendency for us to get worked up around issues that don’t actually make us safe but make for good political soundbites, whether it is refugees or Guantanamo,” he said.

Hopes for a quick political transition in war-ravaged Syria dimmed Thursday as embattled President Bashar al-Assad threw cold water on an ambitious timetable agreed at international talks in Vienna. At the same time, the US held firm to its calls for Assad’s departure, with President Barack Obama insisting Thursday that the war could not end unless the Syrian leader steps down.

“I do not foresee a situation in which we can end the civil war in Syria while Assad remains in power,” Obama said on the sidelines of a trade summit in Manila. Top diplomats from 17 countries met in Vienna Saturday to discuss a way out of Syria’s nearly five-year conflict, which has left more than a quarter of a million people dead. They produced a two-year timetable: a transitional government would be formed and a new constitution written within six months, to be followed by internationally monitored elections within 18 months after that. But in a television interview with Italy’s Rai television, Assad said there could be no transition schedule for elections while swathes of Syria remained out of government control. “This timetable starts after starting defeating terrorism. You cannot achieve anything politically while you have the terrorists taking over many areas in Syria,” he said.

“If we talk after that, one year and a half to two years is enough for any transition.” Damascus refers to all opponents — fighters and activists alike — as terrorists. Syria’s government has insisted that combatting “terrorist groups” including the Islamic State (IS) jihadist organisation should come ahead of any political solution. Assad also rejected the idea of UN observers monitoring elections, saying the world body had “lost all credibility”. In comments to French magazine Valleures Actuelles, the embattled leader said Syria could only accept observers from countries that “were not partisan during the crisis”.

Meanwhile, Russian Foreign Minister Sergei Lavrov said Moscow would be ready to work with the Western coalition striking IS if its members respect Syria’s sovereignty. Russia is “ready to develop with them such forms of coordination that of course would respect Syria’s sovereignty and the prerogatives of the Syrian leadership,” Lavrov told state-run Radio of Russia.

Despite holding diametrically opposed views on the fate of Assad, Russia and France are set to begin coordinating military and security efforts in the anti-IS fight. The remarks by world leaders have rolled back hopes that a political solution was on the horizon. On Tuesday, US Secretary of State John Kerry said Syria could be “weeks away” from a transition.

But Waddah Abed Rabbo, editor-in-chief of Al-Watan daily, which is close to the government, said: “Syria’s president is much more realistic than the Vienna declaration. “Can we imagine elections in Raqa or Deir Ezzor?” he said, naming two provinces where IS has a strong presence. “We must first eliminate this scourge and re-establish the presence of the state throughout the whole country, before beginning the countdown to elections. “ On Wednesday, IS’s English-language magazine said it had killed two hostages by printing graphic photos of two bodies that appeared to be Chinese hostage Fan Jinghui and Norwegian Ole-Johan Grimsgaard-Ofstad.

IS territory across eastern, central, and northern Syria is the target of a US-led air coalition as well as Russian strikes. Air strikes on fuel trucks in IS’s de facto capital, Raqa, killed at least six civilians and wounded 20, the Syrian Observatory for Human Rights said Thursday. Observatory head Rami Abdel Rahman said those killed were oil smugglers and their families, not jihadists. Another eight people were killed in government shelling on Sheikh Maskin, a village in Syria’s southern Daraa province, the Observatory said. Meanwhile, Syria’s army and rebels struggled to pursue talks to reach a 15-day ceasefire in the Eastern Ghouta rebel stronghold east of Damascus.

The two sides had been locked in talks overnight in the hopes of reaching a deal by 6:00 am (0400 GMT), in what would be the first temporary truce in Eastern Ghouta. After hours of relative quiet Thursday morning, Syria’s armed forces resumed shelling Douma, killing six people including two children and a doctor. “The mediators are still at work,” but the situation was less hopeful than this morning, Abdel Rahman said. A Syrian security source told AFP that “the window to reach an agreement has not ended, but we have yet to reach the results stage.” The Observatory said rebel shelling of the capital wounded 16 people Thursday.