GUATEMALA CITY (Reuters) - Guatemala's Fuego volcano erupted on Thursday, spewing smoke and ash into the sky and forcing the evacuation of thousands of people, local emergency services said.

The volcano, 25 miles southwest of the capital Guatemala City, erupted in the early afternoon, sending a cloud of ash one km (half a mile) above the crater, said Sergio Cabanas, director of emergency response in Guatemala's CONRED emergency agency. Some 8,000 people have been evacuated and an additional 23,000 are awaiting evacuation, he added.

A 2010 eruption at Pacaya, one of Guatemala's four active volcanoes, covered Guatemala City 25 miles to the north with a layer of ash, closing the airport and forcing the evacuation of hundreds of families.

(Reporting By Mike McDonald; writing by Gabriel Stargardter; editing by Mohammad Zargham)