A car bomb exploded on Thursday in a campus parking lot at a university in northern Spain, wounding 17 in an attack that officials said followed a warning from the Basque separatist group ETA.

The explosion happened at the University of Navarra in the city of Pamplona at around 1000 GMT, a member of staff at the university said.

"There were other small explosions after the fire set off the fuel tanks in the parked cars nearby," Bernardino Leon, a University of Navarra professor, told the Antena 3 TV channel.

Some 400 people were evacuated from nearby buildings after the explosion, although the rest of the campus continued to function as normal, said the university's director of communication Jesus Diaz.

The blast comes two days after the arrest of four suspected members of armed Basque separatist group ETA -- three of whom were picked up in Navarra.

Spain's interior ministry said the group "were ready to carry an attack, probably in Navarra."

The university said they had received no warning before the blast, but the regional traffic department (DYA) said they got a call at 0853 GMT from a man claiming to represent ETA and speaking in Spanish.

"We had a call in the name of ETA to say that a car was going to going to explode at a university, but without specifying whether it was in Navarra or in Pamplona," a DYA employee told AFP.

Calls to DYA have traditionally been used by ETA to warn of imminent explosions in the Basque country.

Among other demands, radical Basque separatists want to include the separate autonomous region of Navarra in Basque Country.

Founded in 1952, the University of Navarra is a private Catholic university, linked to the Roman Catholic organisation Opus Dei. This attack is the sixth of its kind at the university -- the last one being in May 2002, when a bomb injured three people.

ETA is considered responsible for 824 deaths in its 40-year-long violent campaign for an independent nation in northern Spain and parts of southwestern France. It is classified as a terrorist organisation by the European Union and the United States.

The group resumed its campaign of attacks after breaking its last ceasefire in June 2007, and has been responsible for five deaths, including three Spanish security officers, one soldier and a former Basque Socialist elected official.

The Basque Country already enjoys considerable autonomy and polls show most Basques do not want to split from Spain but a vocal minority is pushing for an independent Basque homeland.

Last month the country's Supreme Court banned two Basque independence parties linked to Batasuna, ETA's outlawed political wing.

Spain's Constitutional Court meanwhile declared illegal the Basque regional government's plan to hold a referendum on self-determination for the wealthy region.

(AFP October 30, 2008)