World leaders to focus on refugee crisis and Syria at UN
World leaders meeting at the United Nations on Monday will be trying to make progress on two intractable problems at the top of the global agenda - the biggest refugee crisis since the Second World War and the Syrian conflict now in its sixth year.
Against a backdrop of rising ethnic and religious tension, fighting elsewhere in the Middle East and Africa, extremist attacks across the world and a warming planet, there are plenty of other issues for the 135 heads of state and government and more than 50 ministers expected to attend, to try to tackle.
"It's no secret there's a lot of fear out there," US ambassador Samantha Power said on Thursday, citing the uncertainties sparked by Britain's vote to leave the European Union, the threat posed by Islamic State, and attacks in many parts of the world by IS and other terrorist groups.
But Syria, where a tense cease-fire brokered by Moscow and Washington came into effect last Monday, remains at the top of the agenda at the UN General Assembly's annual ministerial meeting.
An apparently errant airstrike on Saturday in which the US military may have unintentionally hit Syrian troops while carrying out a raid against IS could deal a crushing blow to the US and Russia-brokered ceasefire.
The ceasefire, which does not apply to attacks on IS, has largely held for five days despite dozens of alleged violations on both sides.
The UN Security Council held a closed emergency meeting on Saturday night at Russia's request to discuss the airstrike.
The meeting offered a harbinger of the difficulties ahead as the US and Russia remain suspicious of each other's intents in Syria.
Ms Power accused Russia of pulling "a stunt" that is "cynical and hypocritical" in calling for the meeting while not taking similar action in response to atrocities committed by Syrian president Bashar Assad's regime.
Russian ambassador Vitaly Churkin said he had never seen "such an extraordinary display of American heavy-handedness" as displayed by Ms Power.
The acrimony over the airstrike could spill over into a Security Council ministerial meeting on Syria scheduled for Wednesday .
Russia was pushing for a resolution to endorse the cessation of hostilities and look ahead, but the US refused to make public details of the ceasefire deal, citing "operational security".
Mr Churkin earlier had called the US unco-operative and said most likely "we're not going to have a resolution".
With the truce still fragile, no sign yet of humanitarian aid deliveries, and supporters and opponents of the Syrian government trading accusations, diplomats said there may be a meeting on Tuesday of some 20 key countries on both sides who are part of the International Syria Support Group to chart the next steps.
The spotlight during the week is also certain to shine on three leaders, who are all scheduled to speak at the assembly's opening ministerial session on Tuesday morning.
UN secretary-general Ban Ki-moon, who steps down on December 31, and US president Barack Obama, who will leave office in January, will be addressing the 193-member world body for the last time.
Prime Minister Theresa May will be speaking less than three months after the vote to leave the European Union.