A statement attributed to al-Qaeda and sent to the London-based daily Al-Quds Al-Arabi has claimed responsibility for the deadly series of bombings in Spain this morning. The statement called the attacks 'strikes against crusaders'.
More than 190 people died and more than 1,200 were injured in the attacks on Madrid's rail network.
The claim from al-Qaeda has not been independently verified.
Earlier, there were reports that Spanish authorities found a tape with Koranic verses in Arabic in a van linked to the blasts.
Another letter purporting to come from al Qaeda network to the same newspaper has warned that a big attack on the United States is in the final stages of preparations. It warned the world to expect a 'Winds of Black Death' strike against America, which it said was 90 percent ready.
The Spanish government initially blamed the Basque separatist group ETA. But ETA's political wing has denied the group was behind the bombings.
Ten explosions hit four trains at three Madrid railway stations during the morning rush hour. The Spanish government has declared three days of national mourning.
The bombs exploded just minutes apart near the central station of Atocha, the southern station of El Pozo and the station of Santa Eugenia. No warning had been given.
Widespread condemnation of attacks
The bombings have been widely condemned.
President Mary McAleese conveyed her sympathies to King Juan Carlos of Spain on the loss of life in the bombings. The President also spoke to the Spanish Ambassador to Ireland to express the condolences of the Irish people.
The Taoiseach described the bombings as an atrocity perpetrated against the Spanish people and an attack on the democratic process.
The US President George W Bush said the attacks were vicious acts of terrorism, and the European Parliament President, Pat Cox, said it was 'the worst act of terror in memory in any EU state'.
Election campaigning suspended
Meanwhile, Spain's political parties suspended campaigning for Sunday's general election.
Mariano Rajoy, leader of the Popular Party, announced that the party had halted its campaign following the attacks, and other parties swiftly followed suit.
The election campaign has focused on the ruling centre-right Popular Party's tough line against ETA.
Spanish officials said late in February that police had averted a bomb attack by ETA planned for the election campaign period.