Defense Secretary Mark Esper said Monday the administration is weighing keeping a small US force in Syria to act as a check on the Islamic State as US troops began crossing the border into Iraq as part of President Trump’s withdrawal.

“We have troops in towns in northeast Syria that are located next to the oil fields, the troops in those towns are not in the present phase of withdrawal,” Esper told reporters during a visit to Kabul, Afghanistan.

“The purpose is to deny access, specifically revenue to ISIS and any other groups that may want to seek that revenue to enable their own malign activities,” he said.

The defense secretary said while there have been discussions about keeping some troops in Syria, “there has been no decision with regard to numbers or anything like that.”

A convoy of armored vehicles carrying US troops into Iraq from northern Syria on Monday was met by angry Kurds tossing potatoes and shouting “America liar,” according to video posted by the Kurdish news agency.

“Like rats, America is running away,” one man shouted in Arabic, the Associated Press reported.

The Kurds, who fought alongside US troops against ISIS terrorists since 2014, have called Trump’s decision to pull American forces from Syria a betrayal.

The president told Turkish President Recep Tayyip Erdogan during a phone call earlier this month that he would pull American forces out of Syria, a move that critics claim gave Ankara free rein to attack the Kurds, whom Turkey considers terrorists.

Trump has said the decision was based on his desire to extricate the US from “endless wars” and to bring troops back home.

Erdogan agreed to a five-day cease-fire brokered last Thursday by Secretary of State Mike Pompeo and Vice President Mike Pence.

The pause in the fighting would allow the Kurds to exit a buffer zone in northern Syria along the border with Turkey.

With Post wires