Spanish police say they have arrested a man who allegedly planned to imitate the 1999 Columbine school killings by planting bombs around a university.

A statement Thursday says police seized 140 kilograms (308 pounds) of bomb-making material when they arrested the 21-year-old in the Balearic island city of Palma de Mallorca a day earlier.

Police said that in his personal diary and Internet blog, the man talked of his admiration for the perpetrators of the Columbine attacks — in which 12 people were killed — and how he planned to place several bombs around a campus in Palma.

They said he had initially tried to purchase guns to carry out the attack but then opted to use bombs.