Despite voting in the appeasement government of Jose Zapatero, Spain is nervous tonight.

MADRID (Reuters) - The Spanish government has called for calm as tensions run high after a series of bombings and a purported al Qaeda threat of more attacks that would “make blood flow like rivers.”

Police patrolled Madrid’s metro Monday, a job normally left to private guards, in the latest of a series of exceptional security measures put in place since 191 people were killed when suspected Islamic militants bombed four commuter trains on March 11.

Up to six of the suspected train bombers blew themselves up Saturday during a police siege in a suburb of the city.

The government says they had been planning further attacks. Police say a handful of accomplices remain at large.

“There could have been a series of Holy Week bombings, probably starting this weekend,” a source close to the investigation said, adding that police were unsure how much of an arsenal remained in the fugitives’ hands.