Two small bombs exploded in tourist towns on Spain's northern coast on Saturday without causing any injuries, in what appeared to be a return to violence by Basque separatists ETA after a long silence.
The explosions took place around midday in the popular coastal resorts of Ribadesella and San Vicente de la Barquera after a warning to Basque separatist newspaper Gara from a caller claiming to belong to ETA.
The attacks came only a day after Spanish authorities had warned that ETA, weakened by scores of recent arrests in France and Spain, could be planning a summer bombing campaign to strike at the country's key tourist industry.
Local media reported the small bomb, packed into a bag left beside a bush in a small park, had exploded on the seaside promenade of San Vicente de la Barquera in the northern province of Cantabria, causing only light damage.
The explosion came only minutes after a similar bomb in Ribadesella, in the neighbouring region of Asturias. Local media reported that this device damaged the wall of a hotel in the coastal resort, which was packed with tourists this weekend for a traditional canoeing championship.
ETA, which has conducted a violent 35-year campaign for an independent Basque homeland in northern Spain, has attacked Spain's tourist industry in the past, bombing hotels in resorts such as Benidorm and Alicante in recent years.
In February, ETA sent warnings to travel agents saying foreign tourists were at risk of violence this summer.
That was before the March 11th train bombs in Madrid that killed almost 200 people and are believed to be the work of al Qaeda-linked Islamic militants.
ETA, which the United States and European Union consider a terrorist organisation, has not carried out a fatal attack for more than a year. It declared a truce in Catalonia - another strongly separatist region - but not in the rest of Spain.
The last violent incident was in September last year when ETA ambushed a police car. One guerrilla died and two policemen were injured in the ensuing shootout.