Trump says in a tweet that he plans a late Wednesday morning statement from the White House where he would discuss the ceasefire between Turkey and American-allied Syrian Kurdish forces.

According to Trump, the Kurds are "safe" and captured Islamic State fighters are "secured" in detention centres.

Trump this month ordered the bulk of the approximately 1000 US troops in Syria to withdraw after Turkey's President Recep Tayipp Erdogan told Trump in a phone call that Turkish forces were readying to invade northeastern Syria.

Turkey's goal was to push back the Syrian Kurdish fighters, considered by Ankara to be terrorists.

Trump said he would "bring our soldiers home" from Syria but then recalibrated and his administration plans to shift more than 700 to western Iraq. Those troops, however, do not have permission to stay in Iraq permanently.

Iraq's Defence Minister Najah al-Shammari told The Associated Press on Wednesday that the US troops will leave the country within four weeks.

Trump's tweet comes one day after Russia and Turkey agreed to deploy their forces across nearly the entire Syrian northeastern border.

The deal cements their rising prominence in Syria as Trump seeks to shrink the American footprint in the region and untangle the US involvement in "endless wars".

US troops in Syria fought for five years alongside Kurdish-led forces in northeast Syria and succeeded in bringing down the IS group there, at the cost of thousands of Kurdish fighters' lives.

Now that territory is set to be handed over to US rivals.

Trump has said he has no problems with Russia and Turkey taking over as power brokers.

The agreement by Russian President Vladimir Putin and Turkey's Erdogan will transform the region.

"I believe that this agreement will start a new era towards Syria lasting stability and it being cleared of terrorism," Erdorgan said. "I hope that this agreement is beneficial to our countries and to our brothers in Syria."

Australian Associated Press