Pressure is building in the United States to stop Turkey from continuing its offensive against Kurdish-held areas in Syria.

US Defence Secretary Mark Esper warned of serious consequences while Treasury Secretary Steven Mnuchin held out the prospect of fresh sanctions against Turkey.

President Donald Trump’s decision to withdraw US troops effectively triggered the Turkish incursion. He has said he would like the US to negotiate a truce between NATO ally Turkey and the Kurds. Turkish President Recep Tayyip Erdogan, however, said the military operation will continue.

According to the UN, more than one lakh people have fled their homes since the offensive began on Wednesday.

President Erdogan says he wants to create a safe zone in northern Syria free of Kurdish militias which could also be home to Syrian refugees. Meanwhile, the Pentagon said its base near the northern Syrian town of Kobane – an area known by Turkey to have US forces present – had seen shell fire from Turkish positions. Turkey has denied deliberately targeting US forces.