Thousands of returning holiday-makers were inconvenienced yesterday by the Basque terror group ETA.

The separatist gang phoned in warnings to the DYA in San Sebastián and the Diario de Teruel at around 2pm, advising that five explosive devices had been placed near main roads in La Rioja, Castilla León, Cantabria and the Basque country.

The warning forced the closure of a number of roads, including the A-1, the AP-1, and the A-67, which were reopened several hours later after no explosives had been found in searches carried out by TEDAX bomb-squad experts.

One very small bomb (approximately 200g), described as a 'petardo' (firecracker) by a police spokesman, did go off, however; at 4.25pm on the N-232 near Fuenmayor in La Rioja, leaving a 50cm-diameter crater, but without causing either injury or material damage.

This is the sixth time in the last three years that the terror gang has disrupted summer holiday traffic in this way.