Repair work on a university building that was hit in a Basque separatist car bombing last week released fumes that sickened nearly 250 people, a school official said Thursday.

Most of the injured were students or university staff, and 94 people remained hospitalized as of midday Thursday, the university said.

A total of 248 people were treated Wednesday for respiratory trouble, nausea and coughing after inhaling the unidentified gases at an administration and classroom building at the University of Navarra in the northern city of Pamplona, university spokesman Javier Diaz said.

The work involving the removal of burned furniture, charred walls and ceilings began right after the attack, he said. The fumes were released by the repair work, not the bomb, Diaz added.

Diaz said the university building has been shut down until investigators determine what the gases are and how to deal with them.

The Oct. 30 attack at a parking lot outside the building where people fell ill left 21 people slightly wounded and set ablaze the ground floor.

The militant Basque group ETA claimed responsibility for the attack and nine others going back to July, including one that killed an army officer.

ETA violence has claimed more than 800 lives since the group emerged in the late 1960s.