It is 50 years since the radical Basque seperatist group ETA was formed, and it celebrated the run-up to its birthday with a series of terrorist attacks. The murder of two civil guards in Majorca yesterday has raised questions about whether the group is in a position to expand its campaign of violence.

Spanish police have stepped up security across the country after two seperate bombings. A massive car bomb exploded outside police barracks in the town of Burgos on Wednesday, injuring 64 people including sleeping children.

And two police men were killed on the island of Majorca yesterday when a bomb went off underneath their patrol car. Officers found a second bomb under another police car and carried out a controlled explosion after they were unable to difuse it.

Perpetrators

Spanish Prime Minister José Luis Rodriguez Zapatero has blamed both blasts on ETA and vowed to bring the perpetrators to justice. 

"I want to assure citizens that the government has instructed security forces to be on maximum alert, that they redouble their dedication, that they further boost their efforts and also that they protect themselves from these vile assasins," he said.

Independence for the Basque country

ETA was established by a group of nationalist students on July 31, 1959, when Spain was still under the grip of the right-wing dictator Francisco Franco.

The group is fighting for independence in the northern Basque region of Spain, and has been blamed for the death of 828 people since it was formed.

In recent months authorities have arrested several key members of ETA, including its charismatic military leader Garikoitz Aspiazu Rubina, or Txeroki, and the latest incidents have raised concern the government is fighting a losing battle.

Difficult to defeat

But Basque political expert Paul Heywood says it is difficult to defeat this kind of organisation but believes the attacks may actually be a sign it is becoming weaker.

"There have been some fairly high profile arrests of ETA leaders since the end of last year and that generally leads to more attempts when the organisation is seen as being threatened.

"It's not that the latest concerted efforts by the Spanish and French governments are failing, it's just as likely to be an indication that actually they are making some progress and this is a reaction against that."

Suspects identified

Sources in Spain say police have identified two suspects in yesterday's incident and it is believed the pair are still on Majorca.

The government's representative for the Balearic islands, Ramon Socías said:

"We are going to make it as hard as we can for them to leave the island. They probably haven't left and are being hidden in an apartment somewhere waiting for the situation to calm down."

Listen to an interview with Paul Heywood from the University of Nottingham