The United States has asked its Western allies to create and possibly enforce a buffer zone in northern Syria, the Wall Street Journal reported, citing unidentified U.S. officials.

The countries approached have yet to agree, potentially slowing a planned U.S. withdrawal announced by President Donald Trump, the newspaper said.

The blueprint is designed to avert a resurgence of Islamic State (ISIS) in the region and possible clashes between NATO ally Turkey and Kurdish forces that are helping the United States defeat the extreme Islamist group, the Journal said.

A European diplomat confirmed to the newspaper that U.S. officials are in talks with their European counterparts about the buffer zone, but there had been no official response because the negotiations were ongoing.

Ilham Ahmed, a senior Kurdish official who represents the political wing of the Syrian Democratic Forces (SDF), said ISIS still presents a danger and has set up sleeper cells in the region.

The buffer zone would encapsulate a 20-mile deep pocket along the Turkish border inside Syria, which would stretch from the River Euphrates to the border with Iraq, U.S. officials said, according to the newspaper.

The United States would offer support via intelligence, surveillance and reconnaissance using drones and other equipment, along with rapid reaction forces if needed. It could also provide logistical support including evacuating casualties, the Wall Street Journal said, citing the plan.

General Joe Dunford, head of the U.S. Joint Chiefs of Staff, returned from Brussels, Belgium last week where he met senior European leaders. Dunford has also been involved in persuading them that the plan will work, the newspaper reported.