Spain's National Court has acquitted four men of trying to use missiles to assassinate then-Prime Minister Jose Maria Aznar on three occasions in 2001.

The court said Wednesday that two missiles, which proved to be faulty, existed but there was no evidence linking the accused to three failed attacks on a plane flying Aznar to the northern Basque region. The armed Basque group ETA later claimed responsibility.

Prosecutors had sought sentences of 70 years in the December trial.

ETA killed 829 people during a four-decade campaign for an independent Basque homeland. It announced a permanent cease-fire in 2011 but has not disarmed.

Aznar, who was premier between 1996 and 2004, survived another ETA car-bomb attack in 1995.