Turkey has asked for major military assistance from the United States in the fight against ISIL in Syria, the Wall Street Journal (WSJ) reported, weeks after Washington announced its plan to withdraw troops from the country.

The substantial request for military support included air raids, logistics and transportation so Turkish forces could finish off the remaining fighters of the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) in Syria, senior US officials were quoted as saying by the WSJ on Friday.

"The Turkish requests are so extensive that, if fully met, the American military might be deepening its involvement in Syria instead of reducing it," the newspaper reported.

The unidentified American officials told the Journal there was little chance Washington would agree to Ankara's requests in full.

US President Donald Trump announced on December 19 his plans to withdraw US troops deployed in northern Syria following a telephone conversation with Turkish President Recep Tayyip Erdogan.

Turkey and the US appeared to agree to coordinate the troops' withdrawal from the area to avoid a power vacuum that could attract a number of parties interested in filling it.

Talks on the fight against ISIL are expected to take place on Tuesday in Ankara.

US officials - including White House National Security Adviser John Bolton, General Joseph Dunford, the chairman of the Joint Chiefs and James Jeffrey, the State Department envoy for Syria - are expected to attend.

The US still has about 2,000 troops in Syria, many of them special operations forces working closely with an alliance of US-backed Kurdish and Arab armed groups known as the Syrian Democratic Forces (SDF).

'US troops should stay'

Meanwhile, the Yazidi minority group has called on the US military to remain in the region amid fears its withdrawal may bring back the threat of ISIL in Syria and Iraq.

In a statement on Friday, the Free Yezidi Foundation, an independent organisation working to help the minority group, warned the US pullout would leave Yazidis and other minorities unprotected and vulnerable.

"The removal of US forces and potentially the cessation of US air strikes... will further diminish SDF's strength on the ground. These areas will then be ripe for return to ISIS control," the group said, using an alternative acronym for ISIL.

Since 2014, ISIL fighters have killed thousands of Yazidi men captured during their attack on the minority.

About 3,100 Yazidis were killed - more than half were shot, beheaded or burned alive - and about 6,800 were kidnapped to become sex slaves or fighters, according to a report published in the Public Library of Science journal, PLoS Medicine.

As the nearly eight-year Syrian war progressed, the SDF gained significant amounts of territory in eastern and northern Syria in its fight against ISIL.

Turkey, however, sees the territorial expansion as a threat as it has long battled Kurdish separatists who want a state of their own.