Madrid  - Spain has stepped up security in case the militant Basque separatist group ETA stages an attack to take revenge of the arrest of its leader Francisco Javier Lopez Pena, the daily ABC said Thursday.

Interior Minister Alfredo Perez Rubalcaba met with police chiefs after returning from an Africa tour earlier than scheduled.

Lopez Pena alias Thierry was captured in south-western France with three other ETA suspects late Tuesday. He is believed to have ordered the main ETA attacks since the government's attempt at a peace process with the group collapsed in December 2006. (dpa)