Nearly 1,000 troops withdrawing from northern Syria are expected to move to western Iraq to continue their campaign against IS, according to the US Secretary of Defense.

"We are still in the process of withdrawing troops from Syria. It will take weeks, not days. The current plan is for these forces to reposition in western Iraq," US Defense Secretary Mark Esper said. with reporters on their way to the Middle East on October 19.

An unnamed US defense official said the plan could change. The decision to send more US troops into Iraq needs to be scrutinized because Iraq is a country that Iran constantly influences.

It is unclear whether the US military is going to use Iraq as a base to conduct ground attacks on Syria or whether it will attack the self-proclaimed Islamic State (IS). The US has more than 5,000 US troops stationed in the country, trains Iraqi forces and helps ensure ISIS does not "revive".

Turkey launched Operation Spring of Peace in northeastern Syria on 9 October, in an attempt to repel the Kurds, which they consider terrorists, from the border and open a safety buffer of about 32 km wide. Trump's earlier abrupt decision to withdraw troops from northern Syria was criticized as a "green light" for the operation, but the US president denied.

US Vice President Mike Pence successfully persuaded Turkey to suspend its military campaign against Kurdish militia (YPG) in northeastern Syria for five days. Trump welcomed Ankara's decision, saying it was a "situation in which all were satisfied" and praised Turkish counterpart Recep Tayyip Erdogan as "good leader".