By GHAITH AL-SAYED
IDLIB, Syria (AP) — Activists say a Kurdish-led force attacked Turkish-backed opposition fighters in northern Syria on Monday, killing at least 13 of the militants. The opposition activists blamed the Kurdish-led Syrian Democratic Forces for carrying out the assault, though the U.S.-backed group did not claim responsibility. Turkey says Syria’s main Kurdish militia is allied with the outlawed Kurdistan Workers’ Party, or PKK, that has led an insurgency against Turkey since 1984 that has killed tens of thousands of people. Turkey since 2016 has conducted three major incursions into northern Syria to clear areas under Kurdish control and create a buffer zone near its border.