UPDATE 4-U.S. withdraws troops from northeast Syria ahead of Turkish offensive

The United States said it was pulling troops from northeast Syria, in a major shift which clears the way for a Turkish military offensive against Kurdish-led forces and hands Turkey responsibility for thousands of Islamic State captives.A U.S. official said American troops had withdrawn from two observation posts on the border, at Tel Abyad and Ras al-Ain, and had told the commander of the Kurdish-led Syrian Democratic Forces that the United States would not defend the SDF from an imminent Turki