Tens of thousands of Spaniards stopped work and observed a few minutes of silence on Monday to honour the latest victim of ETA Basque separatist violence. Maximo Casado Carrera, a 44-year-old prison official, was killed on Sunday in the Basque capital Vitoria when a bomb under his car exploded in the 16th attack blamed on ETA this year. Casado, who will be buried in Vitoria cathedral on Monday afternoon, had been on his way to work at a jail where around 40 convicted members of ETA were imprisoned. Spaniards up and down the country, including Casado's colleagues in state prisons, stopped work at midday to protest at the latest killing by the radical separatists. Nationwide demonstrations were planned later in the day. The attack appeared to be a response to Saturday's march by tens of thousands of protesters in Bilbao, calling on ETA to give up its violent campaign for independence. The rebels are thought to have been responsible for the deaths of about 800 people in a three-decade fight for a separate Basque nation incorporating parts of northern Spain and southern France. This year's wave of killings has made it ETA's bloodiest year since 1992. The group called off a 14-month ceasefire last year and is now the most active guerrilla group in Europe since a truce in Northern Ireland halted activity by the Irish Republican Army. The surge of attacks is believed to be an attempt to crack the conservative Spanish government's hardline stance towards Basque separatism and bring it back to the negotiating table after a single round of peace talks failed last year.