THESSALONIKI — Greece's fire department says three migrants have been found dead following a fire in an abandoned building in the center of the northern Greek city of Thessaloniki.

The three men, believed to have been from Algeria, had been living on the third floor of the abandoned building. Firefighters said the three appeared to have died of smoke inhalation. A fourth man, who told authorities he was from Morocco, survived.

Firefighters said it was not immediately clear what caused the blaze.

Thousands of migrants and refugees make their way to Greece each year from nearby Turkey. Some apply for asylum in Greece, and others try to make their way further north to other European Union countries using smugglers. Many end up sleeping outdoors or squatting in abandoned buildings.