The United States will not make an abrupt and rapid withdrawal of its troops from Syria and will consult closely with its allies on the issue, its special envoy on Syria said on Sunday.

"We've been telling them (allies) continuously this is not going to be an abrupt, rapid withdrawal but a step-by-step withdrawal," James Franklin Jeffrey told the Munich Security Conference, addressing concerns from allies over the US decision to pull out 2,000 troops.

With talks of creating a safe zone on the Turkish-Syrian border, Jeffrey and Turkish Defence Minister Hulusi Akar appeared to differ on what to do about Kurdish-led militias working with the US-backed coalition fighting Islamic State militants.

"We have respect for the territorial integrity of Syria, but the main issue is the safety and security of the Turkish border and Turkish people," Akar said. "The main issue is security to get rid of the terrorists regardless of whether the YPG (Kurds) or Daesh (Islamic State)."