Spain's government says police have prevented a planned jailbreak by ETA Basque separatists and arrested four alleged outside collaborators.

The Interior Ministry says it is investigating three inmates at Huelva prison in southwestern Spain: Jorge Garcia, Igor Solana and Arkaitz Goicochea. It also says it searched the prisoners' cells, and the homes and work places of the suspected collaborators.

The ministry says Garcia and Solana were to have escaped sometime this summer, with Goicochea providing assistance from inside jail.

Some of the arrests and searches took place Saturday.

ETA has killed more than 825 people since the late 1960s in a violent campaign for an independent Basque homeland in northern Spain and southwestern France.