JUDY WOODRUFF:

Turkish military forces launched a major operation inside Syria today to retake the strategic border town of Jarabulus from ISIS.

Turkish and American jets attacked from above, as Turkish tanks and special forces moved into the town. Syrian rebel groups were also part of the operation.

Beyond ousting ISIS from the area, Turkey has another motive for attacking on Jarabulus, to stem the ambitions of the main U.S.-backed Syrian Kurdish militia, known as the YPG, which has been taking over territory from ISIS.

Vice President Biden was visiting Turkey today, and he called upon the Kurds to limit their advances.