Bomb blast in Madrid

A powerful car bomb exploded outside an oil company's headquarters in Madrid yesterday, damaging vehicles and shattering windows in an attack that bore the hallmarks of the Basque separatist group ETA.

Officials said the bomb, estimated to contain about 15kg of explosives, caused no injuries, but three people were treated for shock and a fourth taken to hospital after a heart attack.

Spanish police said the bomb exploded about 1am (11am NZ time) in northern Madrid, close to the Paseo de la Castellana, the capital's busy central artery.

It was the second car bombing in Spain at the weekend. On Saturday, a bomb exploded near Bilbao in Basque country, causing damage but no injuries.