Madrid - Fifteen Spanish police officers are under investigation on charges of torturing two suspected members of the militant Basque separatist group ETA, press reports said Tuesday.

A Basque court said there was evidence that members of the paramilitary Civil Guard had tortured Igor Portu and Mattin Sarasola.

The two were believed to belong to an ETA cell that staged a car bombing at a Madrid airport underground parking lot in December 2006, killing two Ecuadorian immigrants.

One day after his arrest in January 2008, Portu was taken to hospital with injuries including a black eye and a broken rib. Sarasola had also sustained injuries.

Interior Minister Alfredo Perez Rubalcaba then attributed the injuries to the two having resisted arrest.

ETA routinely advises its members to accuse police of torture if detained, according to police sources.

ETA, which has killed more than 800 people since 1968, is listed as a terrorist organization by the European Union and the United States. (dpa)