The Basque institutions, led by Basque government leader Juan José Ibarretxe, called on the population to turn out in force to condemn Friday's murder of two police officers in an attack blamed on the Basque separatist group ETA, which is targeting regional police in its violent drive for independence. The two police officers, a man and a woman, were directing traffic in the town of Beasain, south of San Sebastian, when they were attacked. They had no chance to defend themselves, officials said. The assailants, believed to be a man and a woman, fled the scene and were at still large. ETA once again is destroying families and once again it is destroying the Basque Country, Basque regional President Juan Jose Ibarretxe said from the Czech Republic, where he cancelled an official visit to return home immediately. The body of the female officer -- Ana Isabel Arostegi, 34 -- remained at the scene, covered by a blood-stained sheet several hours after the shootings. She was the married mother of three children and becomes the first female officer in the Basque police force to be killed by ETA, a police union official said. The male officer, who died in hospital, was identified as Francisco Javier Mijangos, aged 32. A symbol of Basque autonomy, the Basque police -- known as the Ertzaintza -- are controlled by the local authorities and not by the central government in Madrid. But ETA announced in March it would target officers of the force, labelling them repressive despite their Basque roots. Arostegi and Mijangos became the 12th and 13th members of the Basque police force killed by ETA, the union said. The two deaths increase to 15 the total pinned on ETA this year and to 38 the number killed since the outlawed group called off a 14-month ceasefire in December 1999. About half the two million people in the wealthy Basque Country of Spain support greater autonomy or independence, but ETA violence is roundly condemned. A pro-ETA political party received only 10 per cent of the vote in May regional elections. The most active guerrilla group remaining in Western Europe, ETA is listed by the US State Department as a Foreign Terrorist Organisation (FTO). Spanish Prime Minister Jose Maria Aznar condemned the attack from the Ibero-American summit in Lima, Peru.