DUBAI : The purported claim from the Al-Qaeda terror network that it carried out the atrocities in Madrid set the world back on edge as stock markets plunged, nations tightened security and fears of worse to come spread. Spain's government has named the armed Basque separatist group ETA as prime suspect for the killing of 199 people Thursday when 10 bombs blew up at three Madrid rail stations during morning rush hour, injuring 1,400 more. US President George W. Bush declared, "We don't know who did this yet," adding "I wouldn't rule anybody out." But the unverifiable claim of responsibility...