WASHINGTON - The United States does not support a planned Turkish incursion into northeast Syria "in any shape or form" as it will not make the region any more secure against threats from Islamic State, a senior State Department official said on Monday."We made it clear (to the Turks) that we do not support this operation," the official said while briefing reporters. "We think this operation is a very bad idea." He said such an operation would not make the region any safer.Turkish President Tayyip Erdogan, in a phone call with U.S. President Donald Trump late on Sunday, sought U.S. support for Ankara's planned incursion, the official said, but added that Trump declined."Erdogan thought all along that in the end the President would give some kind of military backing," the official said.The Trump administration announced late on Sunday it was withdrawing U.S. troops from northern Syria, citing the cost but opening the way for a Turkish strike on Kurdish fighters long aligned with Washington.The United States has since pulled back a small number of forward deployed forces on the border with Turkey, largely not to jeopardize the lives of any American soldiers. The official said fewer than two dozen had been pulled back."Beyond that there is no change in our military posture in the northeast (Syria). We are reviewing our military position there," he said and added that Washington would go on controlling the airspace in the region.A pullout, opposed by many in Congress, including members of Trump's own Republican Party, also hands responsibility to Turkey for thousands of jihadist prisoners.The Turkish presidency said that during the call with Trump, Erdogan had expressed his frustration with the failure of U.S. military and security officials to implement the agreement between the two countries on a safe zone.The NATO allies agreed in August to establish a zone in northeast Syria along the Turkish border. Turkey says the United States moved too slowly to set up the zone. It has repeatedly warned of starting an offensive on its own into northeast Syria.When asked about Ankara's plan to resettle millions of Syrian refugees back into northeast Syria, the official said: "That is probably the craziest idea I've ever heard."