Turkey, faced with a possible new wave of Syrian migrants and dozens more dead Turkish soldiers in Idlib, will no longer stop Syrian refugees from reaching Europe, a senior Turkish official said as President Tayyip Erdogan chaired an emergency meeting.An air strike by Syrian government forces in Syria's northwest Idlib region killed 29 Turkish soldiers and seriously wounded others, the local governor in Turkey's southeastern province of Hatay said separately early on Friday.The US said that it supports Turkey following the reported attack. "We stand by our NATO Ally Turkey and continue to call for an immediate end to this despicable offensive by the Assad regime, Russia, and Iranian-backed forces," a State Department representative said in a statement. Nearly a million civilians have been displaced in Idlib near the Turkish border since December as Russia-backed Syrian government forces seized territory from Turkey-backed Syrian rebels, marking the worst humanitarian crisis of the country's nine-year war.The threat to open the way for refugees to Europe would, if executed, reverse a pledge Turkey made to the European Union in 2016 and could quickly draw Western powers into the standoff over Idlib and stalled negotiations between Ankara and Moscow.In anticipation of the imminent arrival of refugees from Idlib, Turkish police, coast guard and border security officials have been ordered to stand down on refugees' land and sea crossings, the Turkish official told Reuters."We have decided, effectively immediately, not to stop Syrian refugees from reaching Europe by land or sea," said the official, who requested anonymity. "All refugees, including Syrians, are now welcome to cross into the European Union." The burden of hosting refugees "is too heavy for any single country to carry," the official said.Turkey hosts some 3.7 million Syrian refugees and has repeated it cannot handle more. Under a deal agreed in 2016, the European Union has provided billions of euros in aid in return for Ankara agreeing to stem the influx of migrants into Europe.TROOP DEATH TOLL 50 THIS MONTHSyrian President Bashar al-Assad's forces, supported by relentless Russian air strikes, have pushed hard in recent months to retake the last large rebel-held region in northwest Syria after the country's war that has displaced millions and killed hundreds of thousands.NATO-member Turkey has sent thousands of troops and heavy military hardware into Idlib province in recent weeks to back the rebels it supports against the offensive, and had already seen 21 troops killed so far this month.Erdogan has warned that Turkey would launch a full scale offensive to repel Syrian forces unless they pulled back. He held an emergency meeting with staff for several hours late on Thursday to discuss the attack, which raised the military death toll to 50 so far this month.Rahmi Dogan, the Hatay governor, said 36 Turkish troops were wounded in Thursday's air strike.Turkey's communications director Fahrettin Altun said that, in retaliation, "all known" Syrian government targets were being fired on by Turkish air and land support units. EU-TURKEY MIGRANT ACCORDAs fighting raged along several fronts on Thursday, the United Nations said it was having "catastrophic" humanitarian consequences, with at least 134 civilians including 44 children killed in February alone, and schools and hospitals destroyed.Seven children were among 11 people killed when an air strike hit a school in northern Idlib on Tuesday, according to the United Nations, which has called for an immediate ceasefire.Turkey has urged Europe to do more to ease the crisis in Idlib, and last year Erdogan said his government could "open the gates" for migrants to Europe if it failed to act.The 2016 EU-Turkey accord aimed to help end the chaotic arrival of migrants and refugees, most of them fleeing war and poverty in the Middle East, Africa and Asia, after more than a million reached Europe in 2015.Under the agreement, migrants and refugees who cross the Aegean Sea illegally are sent back to Turkey. But Ankara has said funding from Europe was slow to materialize and paltry next to the $40 billion it says it has spent.Turkish and Russian officials held a third round of talks in Ankara on Thursday. Two previous rounds have not yielded a ceasefire deal.Earlier on Thursday, Russian state television said Turkish military specialists were using shoulder-fired missiles to try to shoot down Russian and Syrian military aircraft over Idlib.In Washington, the Pentagon said US Defense Secretary Mark Esper spoke with his Turkish counterpart on Thursday and they discussed Idlib and Libya."As President (Donald) Trump said on Tuesday, and as discussed in today's call, we are exploring ways the United States can work together with Turkey and the international community," a Pentagon readout of the call said.Erdogan and Trump may hold a phone call to discuss Idlib after the attack on Turkish soldiers, two Turkish officials told Reuters.