US-Russia ‘gaps of trust’ stymie hopes for Syria ceasefire

US president Barack Obama has said a lack of trust between Washington and Moscow is hampering efforts to agree a ceasefire in Syria and co-ordinate international action against Islamic State and other radical groups operating there.

Mr Obama described talks with Russian president Vladimir Putin on Monday as "candid, blunt, business-like" but acknowledged that progress was lacking on Syria, as several explosions killed dozens of people in mostly government-held areas.

The two leaders met on the sidelines of a G20 summit in China, where Turkish president Recep Tayyip Erdogan urged the US and Russia to establish a no-fly zone over northern Syria and to push for a new ceasefire in the key city of Aleppo in the coming days.

Mr Obama said talks with Mr Putin centred on how “to institute a meaningful, serious, verifiable cessation of hostilities in Syria, and our capacity to provide some humanitarian relief” there.

The US leader said a previous bid to reduce violence had unravelled and the forces of Syrian president Bashar al-Assad – backed by Moscow – were again “bombing with impunity” and driving more people to join radical militia groups.

Russia has characterised all armed opponents of the Assad regime as “terrorists” and targeted them with air strikes, including groups that the US supports and describes as “moderate”.

Mr Obama said he and Mr Putin “had some productive conversations about what a real cessation of violence would look like, that would allow both us and Russia to focus our attention on common enemies”, like Islamic State, also known as Isis, and Jabhat Fateh al-Sham (formerly Jabhat al-Nusra).

“But given the gaps of trust that exist, that’s a tough negotiation and we haven’t yet closed the gaps in a way that we think would actually work,” he added.

Russian media quoted Mr Putin as saying that he and Mr Obama understood each other’s positions on Syria better after the talks, and that he hoped their countries’ relations would improve from their current “abnormal” state.

US secretary of state John Kerry and Russian foreign minister Sergei Lavrov are expected to continue discussions on Syria in the coming days, despite failing in China for the second time in a fortnight to agree a ceasefire plan.

Mr Obama and Mr Putin also discussed Ukraine, where Russia has annexed Crimea and fomented a separatist conflict that has killed 10,000 people.

Mr Obama said Washington would not lift economic sanctions on Russia until the beleaguered Minsk peace plan was fully respected.

The US, Russia, Germany and France agreed that efforts to implement the pact "should increase in urgency over the next several weeks", Mr Obama said, adding that it remained to be seen if Mr Putin was serious about ending the conflict.