Spanish authorities are secretly preparing to deal with a significant terrorist attack in one of the country’s popular tourist resorts, and have ordered police to step up security measures, according to an internal memorandum distributed to regional forces last week.

The warning comes after a spate of minor bombings by the Basque separatist group ETA, timed to disrupt Spain’s tourist industry at its busiest period.

The latest attack, a blast outside the Sol Aloha Puerto hotel, in the Costa del Sol resort of Torremolinos, was the fifth in 10 days and, although nobody was hurt in the explosion, local police say the device was “perfectly capable of killing”.

The Spanish interior minister, Alfredo Perez Rubalcaba, said that he had no doubt the bombing was the work of ETA, adding that the discovery of a rucksack containing bomb-making equipment in a quarry on the outskirts of the town showed further attacks were planned.

Intelligence gathered following the arrest of an ETA cell on July 22 suggests that a “big attack” will target one of Spain’s popular annual ferias, which are a magnet for locals and tourists alike.

“The interior ministry warns that the terrorists could try to attack somewhere holding a fair with a massive public presence and therefore a greater police presence,” a memorandum says.

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