Spain was building up to a tense Easter weekend holiday today amid awareness that a group of Islamic militants who blew themselves up when cornered by police last Saturday had planned more attacks this weekend.
Easter week is marked by huge public processions in largely Catholic Spain, a nervous time for security forces trying to avert new attacks.
Police and troops were deployed to guard dams, power plants, high-speed rail lines and other possible targets in a country still shaken by Madrid train bomb attacks that killed 191.
Nearly a month after those bombings, believed to have been carried out by al-Qaeda militants, several of a group of suspects are still unaccounted for.
Police are now holding 18 people, most of them Moroccans, and the government says they, and the seven who blew themselves up in Saturday's raid on a Madrid apartment, account for most of those involved in the March 11th bombings.
But La Razonnewspaper said today investigators believe there are more "sleeper cells" of Islamic militants, unrelated to the group responsible for the Madrid bombs.
Security has been stepped up around Spain since the thwarted attempt to bomb a high-speed rail line on Friday and since the suicide bombing on Saturday. Sources close to the investigation have said the suicide bombers may have been planning a series of Holy Week attacks before getting cornered, based on two or three prepared bombs and loose explosives found in the apartment.
Holy Week in Spain sees processions of penitents, the largest in the southern city of Seville where thousands of devotees dressed in tunics and wizard-like caps carry religious floats and crosses through the streets each night, climaxing early on Good Friday morning.