MADRID, June 8, 2008 (AFP) - An explosion blamed on the Basque separatist group ETA damaged the printing press of a Spanish newspaper near the city of Bilbao but nobody was injured, police said Sunday.

'This explosion has been staged by ETA,' a spokesman said of the early morning blast.

El Correo, the main newspaper in the Basque region, said on its website that about 50 people were working at the time of the blast at 3:00 am (0100 GMT) and had to be evacuated.

It too blamed ETA for the blast in the industrial zone of Zamudio and said a wall had been partly demolished.

ETA is blamed for the deaths of 823 people in its 40-year campaign of bombings and shootings to carve a Basque homeland out of northern Spain and southwestern France.

On Friday, it claimed responsibility for the killing of a policeman in a bomb blast on May 14 as well as three other attacks, and warned that its armed campaign would continue.