AKCAKALE, Turkey (AP) — Turkey launched airstrikes, fired artillery and began a ground offensive against Kurdish fighters in northern Syria on Wednesday after U.S. troops pulled back from the area, paving the way for an assault on forces that have long been allied with the United States.

Turkish President Recep Tayyip Erdogan announced the start of the campaign, which followed the abrupt decision Sunday by U.S. President Donald Trump to essentially abandon the Syrian Kurdish fighters, leaving them vulnerable to a Turkish offensive that was widely condemned around the world.

The decision was a...