At least 173 people were killed and more than 400 injured when co-ordinated explosions tore apart packed rush-hour trains in Madrid yesterday, the Interior Ministry said.
Authorities blamed the Basque separatist group ETA for the attacks, which would be the worst ever by the separatist group.
Judicial sources had earlier confirmed that at least 120 people died in the explosions that opened up trains like tin cans and splattered blood everywhere at one of the three stations targeted.
The bombings came four days before Spain's national elections on Sunday. The ruling Popular Party immediately suspended its election campaign following news of the atrocity.
The party's leader, Mariano Rajoy, said: "Spain is in mourning. These criminal terrorists are sowing death and suffering not just in Madrid but in the whole of Spain."
The Labour Minister, Eduardo Zaplana, told Cadena Ser radio station: "This is a collective killing by the criminal band which is ETA."
However, Arnaldo Otegi, leader of the banned Basque separatist party, Batasuna, said he "refused to believe" that ETA was responsible and blamed "the Arab resistance" instead. Spain was one of the strongest supporters of the US-led invasion of Iraq last year.