The head of the United Nations on Friday launched a $500 million flash appeal to help some 900,000 people displaced during a ferocious assault by Russian-backed regime forces on northwest Syria.
Addressing reporters in New York, UN secretary-general Antonio Guterres warned of rising tensions in Idlib province, where Syrian government and Turkish forces have repeatedly clashed in recent weeks in a worrying escalation of the conflict.
"The fighting is now advancing into areas with the highest concentrations of people-including the displaced-and threatening to strangle humanitarian lifelines," said Guterres, a former Portuguese prime minister.
"We are revising our plans and issuing an urgent appeal to donors for an additional $500 million to cover the needs of the newly displaced people over the next six months."
Guterres described miserable "human suffering" in northwestern Syria — the last rebel held bastion in the country's nearly nine-year civil war — where some 2.8 million people need food, water, medicine and other aid.
"For almost a year we have seen a series of regime ground offensives supported by Russian airstrikes. This month there have been repeated deadly clashes between Turkey-led forces and pro-regime fighters," added the UN chief.
"I have repeatedly called for an immediate ceasefire in Idlib to end the humanitarian catastrophe and now also to avoid an uncontrollable escalation."
Russia and Turkey back opposing sides in Syria's war, but have nevertheless tried to broker a political deal. Bashar al-Assad's assault on the northwest has upset this effort, seeing Ankara and Moscow accuse each other of breaking de-escalation deals in the region.
Turkey hosts some 3.7 million Syrian refugees and has said it cannot absorb a new exodus. Ankara says it will use military power to repel Syrian advances in Idlib and to help tackle the unfolding humanitarian crisis.
"The message is clear: There is no military solution to the Syria crisis. The only possible solution remains political," added Guterres. "This man-made humanitarian nightmare for the long-suffering people of Syria must stop. It must stop now."