Five low-potency bombs placed in gas stations in highways leading out of Madrid Friday caused massive traffic jams on a busy holiday weekend. Spain's Interior  Minister blames the Basque terrorist group ETA.

A phone call made around 5:30 in the afternoon local time  to the radical, pro-independence Basque newspaper GARA in the name of the violent group ETA announced that five small bombs had been set near gas stations along highways leading out of Madrid.

Thanks to prompt police action the stations were evacuated and the five bombs, exploded without causing serious material damage around an hour later. Only slight injuries to the eardrums of two policemen were reported.

But traffic was snarled up for miles on five major highways as Madrid residents headed out of the city to enjoy national holidays set for Monday and Wednesday.

Interior Minister José Antonio Alonso said that all evidence pointed to the Basque terrorist Group as responsible for setting the bombs.

The Minister pointed out that the bombs used were of low potency and that there was no indication that ETA had a cell based in Madrid.  The terrorist organization has been blamed for 21 bomb attacks, including these, this year in various parts of Spain. All of them have been of low potency, and have claimed no lives.

In early October French and Spanish police carried out an operation in the south of France near the Pyrenees leading to the arrest of two of ETA's top leaders and the seizure of an small arsenal of weapons and explosives.

In a 30 year struggle for the establishment of a Basque state in the north of Spain and South of France, ETA has killed more than 800 people.