The US has called for an international boycott of a Russia-planned conference to help return millions of Syrians who have fled their war-ravaged home, which is set to take place in Damascus next month. Washington’s deputy ambassador to the UN, Richard Mills, said it was “totally inappropriate” for Moscow, which is backing Syrian President Bashar Al Assad, to oversee the return of refugees. The UN says that more than 5.6 million people have fled Syria since fighting erupted in 2011 – mostly to Lebanon, Turkey and Jordan – in a conflict that has divided major powers. “It is the strong belief of the US that this conference is counter-productive and it is totally inappropriate for any military organisation to manage refugee returns in Syria, Russia or otherwise,” Mr Mills told an online meeting of the UN Security Council on Tuesday. “The US will not attend the conference. We strongly urge the UN and all others to forgo attendance as well at this conference that has been orchestrated by those responsible for the refugees fleeing in the first place.” Mr Mills said Syria was not ready for “large-scale” refugee returns and warned an influx could cause “instability and a revolving door of displacement”. Moscow has sidelined the UN and major refugee host countries such as Germany and Turkey in the process, he said. Russian defence chiefs and Syrian Foreign Minister Walid Al Muallem will host talks on returning Syrian refugees in Damascus on November 11 and 12, despite safety concerns from the UN, aid groups and some western countries. Russia’s UN ambassador, Vassily Nebenzia, blasted an “anti-Syrian bias” and efforts to “discredit this humanitarian initiative”, which is aimed at rebuilding the war-ravaged country and “create normal living conditions for its citizens”. The conference would focus on the “laborious” and costly effort to rebuild infrastructure, homes, communications systems and remove mines and other unexploded weapons, Mr Nebenzia said. “No matter how hard the opponents of Damascus try to prevent it, people want to return and they do return home," he said. "Nobody talks of forced return. People do it voluntarily. It is a fact that cannot be denied." France’s UN ambassador, Nicholas de Riviera, said the UN’s refugee agency should take the lead in returning Syrians and said Paris would “oppose any attempt to politicise the subject of refugee return”. “The conditions for the safe, dignified and voluntary return of Syrian refugees are not yet in place," Mr Riviera told the council. "Only a credible political process will allow returns. No conference can achieve this."<br/> Geir Pedersen, the UN's envoy to Syria, who met Mr Al Muallem and other officials in Damascus this weekend, called for a "serious and co-operative effort" to process the "safe, dignified, informed and voluntary return" when the country is calmer.<br/> Council members spoke online against a backdrop of escalating tension in north-west Syria, where suspected Russian air strikes on a camp killed dozens of Turkish-backed Syrian rebel fighters on Monday. Ankara has backed rebels who sought to topple Mr Al Assad. But the Syrian president, backed by Iran and Russia, has driven back an opposition that once threatened to encircle Damascus and is now confined to a small pocket in the country’s north-west.