Madrid ( CNN ) -- Spanish police seized a total of 1,600 kilos of bomb-making materials this week from suspected ETA hideouts -- the largest haul ever against the Basque separatist group in Spain . Authorities also arrested three ETA suspects this week -- including one during a seizure on Thursday -- in the latest actions in a police crackdown against ETA despite its unilateral cease-fire declared last January 10 . The Spanish government has vowed to keep up the pressure on ETA because the outlawed group , listed as a terrorist organization by the European Union and the United States , has broken cease-fires in the past . The police on Tuesday arrested two men in northern Spain suspected of supplying explosives and bomb-making materials to ETA . A search of their property turned up 850 kilos ( 1,870 pounds ) of bomb-making components . Then on Thursday , the police discovered another 750 kilos ( 1,650 pounds ) of explosives and components at various suspected hideouts , and arrested a third suspect . The two seizures totaled about 3,520 pounds . ETA is blamed for more than 800 deaths in its long fight for Basque independence , many of those due to car bombs and package bombs . Last month in France , police arrested the suspected military chief of ETA , in charge of commandos who carry out the bombings . In recent years , the police have arrested in succession a series of suspected ETA military chiefs as ETA replacements step in to fill the vacant position at the top . Also last month , in northern Spain , police arrested four key ETA suspects who authorities said had tried to operate under police radar , carrying on ostensibly law-abiding lives but secretly working for ETA . Police seized 200 kilograms ( 440 pounds ) of explosives in those raids . Top government officials have said ETA appears to be weaker than ever , but they have warned that the group still has the capacity to kill . The Socialist government and the main opposition conservative party have said ETA 's current unilateral cease-fire is not enough , and that only a commitment to permanently end the violence and lay down weapons would suffice . Deputy Prime Minister Alfredo Perez Rubalcaba said last month , `` The government 's anti-terrorist policy has not changed at all because ETA has not definitively abandoned its weapons . And as long as it does n't , the police will continue to arrest them , one after another . ''
Police seize 750 kilos of bomb-making materials from suspected ETA hideouts . This week , more than 1,600 kilos of explosives and components have been found . ETA is blamed for more than 800 deaths in its campaign for Basque independence . Officials say ETA appears to be weaker than ever , but warn it the group is still deadly .