Evidence points to Al Qaeda in addition to their claims of credit:
MADRID, Spain – The wave of bombings Thursday that killed at least 190 train commuters and injured 1,240 others could have been the work of Muslim extremists, Spanish officials said after finding a van carrying detonators and an Arabic-language tape containing verses from the Quran.
Spain has a long history of ETA terrorism, and a longer history of conflict with Islam, so the question is how much influence this tragedy will have by way of stiffening the Spaniards’ resolve to carry out the war to its conclusion. While PM Aznar has been a strong supporter of the Coalition in Afghanistan and Iraq, he’s not had much support from his people.
That may change now.
UPDATE: Tim Blair points to Iberian Notes, a leading Spanish blog.
Why does Arabic and Quran quotes automatically mean Al Qaeda ? They have a consistent history of declaring responsibility, within a very short time.