The airport of Zaragosa in northern Spain has been evacuated due to a bomb alert.Authorities received an anonymous call in the name of the Basque terrorist group ETA saying that a grenade-launcher was aimed at the airport. The alert comes amid National Day celebrations in Spain. Today is also Armed Forces day, attended by the royal family, government leaders and a number of foreign dignitaries. The airport was already the target of a rocket attack in June. No one was injured. ETA has killed more than 800 people since 1968 in its fight for Basque independence.