The prime minister will join Prince Charles, German Chancellor Gerhard Schroeder, French President Jacques Chirac, U.S. Secretary of State Colin Powell and other foreign dignitaries for the service at Madrid's Almudena Cathedral on Wednesday, the BBC reported.
The attacks on March 11 left 200 people dead and more than 1,200 injured when 10 bombs exploded on four trains during the morning rush hour. Fourteen people have been arrested in the investigation.
Spain's Prime Minister elect Jose Luis Rodriguez Zapatero has said he wants to withdraw Spain's 1,300 troops from Iraq, a decision Blair hopes to persuade Zapatero to reconsider, the BBC said.
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