"There doesn’t seem to be any strategic rationale for the decision. And if there’s no strategic rationale for the decision then you have to ask, why was the decision made?" Clark said during a TV interview with CNN.
Clark, a retired US Army general, said that people around the world, including US allies in the Middle East, are asking whether the decision came as a result of Erdogan blackmailing Trump.
"Was there a payoff is or something? Why would a guy make a decision like this? Because all the recommendations were against it," Clark said.
The comment followed Sunday's statement by Trump about his "long and productive" phone call with Erdogan on the same day, during which they discussed "expanded" bilateral trade and the planned pullout of US troops from Syria.
Last week, Trump announced that the United States would withdraw its roughly 2,000 troops from Syria since the Daesh* terror group had been defeated. However, the White House later clarified the decision does not mean the end of the US-led international coalition's fight against the Islamic State.
Democratic and Republican lawmakers in the US Congress who have supported US military engagement and intervention in the world criticized Trump’s decision saying that a US troop withdrawal from Syria will lead to the reemergence of the Islamic State and aid Russia, Turkey and Iran’s interests in the region.
*Daesh — a terrorist group banned in Russia