Trump said he spoke with the Turkish President about the substantial economic development possible between the two nations.

After the phone call, Trump tweeted: "Spoke w/ President Erdogan of Turkey to advise where we stand on all matters including our last two weeks of success in fighting the remnants of ISIS, and 20 mile safe zone. Also spoke about economic development between the U.S. & Turkey - great potential to substantially expand!"

Trump and his threat:

Trump has threatened that Turkey will be 'devastated economically' if they attack the Kurdish forces in Syria.

"Starting the long overdue pullout from Syria while hitting the little remaining ISIS territorial caliphate hard, and from many directions. Will attack again from existing nearby base if it reforms. Will devastate Turkey economically if they hit Kurds. Create 20 mile safe zone," Trump tweeted.

He also said that he will not like the Kurds to provoke Turkey also.

"..Likewise, do not want the Kurds to provoke Turkey. Russia, Iran and Syria have been the biggest beneficiaries of the long term U.S. policy of destroying ISIS in Syria - natural enemies. We also benefit but it is now time to bring our troops back home. Stop the ENDLESS WARS!," Trump said.

Trump said the time was correct to withdraw US troops from Syria.

Over a long period of time, US forces have fought alongside a Kurdish militia in northern Syria against terrorist group Islamic State.

The Turkish government considers People's Protection Units (YPG) as terrorists.

President Recep Tayyip Erdogan has spoken angrily about American support for the group and vowed to crush it, reported BBC.

As per BBC report, President Trump shocked allies and faced strong criticism at home last month when he ordered US forces to immediately begin withdrawing from the approximately 30% of Syria controlled by the YPG-led Syrian Democratic Forces (SDF) alliance.

Image: Donald Trump Facebook page