The Turkish military offensive in Syria has displaced at least 160,000 civilians, the UN secretary general said Monday in a statement urging an "immediate de-escalation."
Secretary-General Antonio Guterres "is gravely concerned over the military developments in northeast Syria," the statement said.
It said Guterres was urging "all parties to resolve their concerns through peaceful means," adding that "civilians not taking part in hostilities must be protected at all times."
Guterres also expressed "serious concern" that the Turkish onslaught could lead to the "unintended release of individuals" associated with the Islamic State group.
Some of the Kurdish forces guarding IS prisoners or their families have been pulled away to fight the Turks, raising fears that many IS militants might be able to escape.
Guterres also demanded "sustained, unimpeded and safe humanitarian access to civilians in need" to allow the United Nations and its humanitarian partners to carry out aid work.
After President Donald Trump said over the weekend that he was withdrawing the US troops who had effectively prevented a Turkish incursion, Syrian government forces on Monday were nearing the border with Turkey for the first time in years after striking a deal with the embattled Kurds.