Spain said yesterday that ETA's two top leaders had been arrested in a police swoop in southwestern France in what it said was a major blow against the armed Basque separatist group. Today is a very important day in the fight against terrorism, Interior Minister Angel Acebes said, confirming the arrest near Bordeaux on Monday night of ETA suspects Juan Antonio Olarra and Ainhoa Mugica. Accusing the pair of participating in a series of bloody ETA attacks, Acebes said the leadership of the terrorist organisation ETA and its two top leaders had been arrested. However, ETA is known not to rely on a vertical command structure, instead using committees of leaders, which has allowed it to withstand high-level arrests in the past. Olarra had 20 arrest warrants outstanding against him, 11 of them international warrants, Acebes told a news conference. Mugica was wanted on nine national and three international arrest warrants, he said. Olarra, 35, and Mugica, 32, both from San Sebastian in Spain's northern Basque country, are a couple, according to French police. A French woman, Saroya Galarraga, was also arrested in Monday night's swoop, Acebes said. He said Galarraga was in charge of providing cover for ETA members in France, such as renting apartments for them. Yesterday, French police arrested Galarraga's boyfriend, a 21-year-old Frenchman, close to the Spanish border, a source close to the investigation said. His name and what he was suspected of were not disclosed, and he was not charged. Prime Minister Jose Maria Aznar's centre-right government takes a hard line against ETA, which has killed 836 people and injured more than 2'300 since 1968 in a bloody campaign for an independent Basque homeland in north Spain and southwest France. While cracking down on ETA activities at home and in cooperation with French authorities, Spain's government has also moved against radical Basque political party Batasuna, which it accuses of being ETA's political wing. High Court Judge Baltasar Garzon last month suspended Batasuna's activities for three years and the government is seeking a complete ban. The government of Spain's Basque region, run by the mainstream Basque Nationalist Party, said on Tuesday it would sue Garzon for perverting the course of justice in his clampdown on Batasuna. The moves against Batasuna have prompted repeated clashes between police and Batasuna supporters in the Basque country. Acebes said Monday's arrests showed Spain's strategy for combating the guerrilla group was on the right track. He said he had spoken to French Interior Minister Nicolas Sarkozy on Tuesday to congratulate him on the arrests. Spanish newspapers said Olarra and Mugica's apartment at Talence on the outskirts of Bordeaux was watched after a suspicious neighbour contacted police. El Pais newspaper said the suspects were carrying pistols when they were arrested. Acebes said both Olarra and Mugica belonged to ETA cells known as the Donosti, Levante and Madrid commandos until 1997. He alleged they took part in the murder of the former Constitutional Court chairman, Francisco Tomas y Valiente, in February 1996 and the killing of magistrate Rafael Martinez Emperador a year later. He said they were also involved in a December 1995 bombing in Madrid which killed six navy employees. Acebes said the arrested man and woman joined ETA's leadership in 1997 and 1998, reporting to the head of ETA operations, Francisco Garcia Gaztelu. When Garcia was arrested in France in February 2001, they replaced him, supplying equipment and setting targets for ETA attacks, he said.