US Secretary of State Rex Tillerson has sought to reassure allies that Washington was not tilting towards Moscow over the Syrian conflict, arguing today that the US backed UN efforts to broker a political solution to the war, officials and diplomats said.

Tillerson also said military ties with Russia hinged on its stance towards rebels fighting the government of President Bashar al-Assad, who Russia backs. Countries opposed to Assad met on Friday for the first time since Donald Trump took office as U.S. president in a bid to find common ground ahead of UN-backed peace negotiations in Geneva next week.

All eyes have been on Washington and its approach to ending the war in Syria, given promises by Trump to build closer ties to Russia, especially in the fight against Islamic State. Trump's policy on Syria has been unclear.

Western diplomats said that in talks on the sidelines of a G20 foreign ministers' meeting, Tillerson had stressed the importance of sticking to UN efforts to reach a political solution based on Security Council Resolution 2254 under the special envoy on Syria, Staffan de Mistura. The envoy will convene a new round of peace talks among Syrian factions next Thursday.

The diplomats also said Tillerson had stressed that Moscow's position to align itself with the Syrian government to label all rebels as terrorists would make military cooperation between Washington and Moscow complicated.

Assad is in his strongest position since the early days of the civil war, which began as a popular uprising in the spring of 2011, before spiralling into a war that has killed up to 400,000 combatants and civilians. The US, along with Gulf Arab States and Turkey, backs rebel forces but the situation is complicated by the role of hardline Islamist factions, including Islamic State, in the anti-Assad movement who are opposed by both Washington and Moscow.

Russia has sought to revive diplomacy since its air force helped to defeat rebels in Aleppo in December, the Syrian leader's biggest victory to date. Nearly six years into the war, Assad seems militarily unassailable thanks to the decisive backing of Russia and Iran. It has held a series of parallel intra-Syrian negotiations in coordination with Turkey and Iran in the Kazakh capital Astana to reinforce a shaky ceasefire and has tried to expand the scope to cover political aspects.

On Thursday, Russian Foreign Minister Sergei Lavrov said the US supported the Russian-sponsored talks, which ended with no joint agreement and opposed Syrian groups. "The Russians are trying to pilot a separate process," said one diplomat. "Geneva is an extremely fragile process and we want to avoid it being chaotic."

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.