ALEXANDROUPOLIS, Greece — Firefighters scouring the area of a major wildfire in northeastern Greece burning out of control for a fourth day found the bodies of 18 people, authorities said Tuesday. They were examining whether the group might have been migrants who entered the country through the nearby border. The discovery in the Avanta area of the city of Alexandroupolis came as hundreds of firefighters battled dozens of wildfires breaking out across the country, fanned by gale-force winds.