Key dates in history of Basque group ETA

On December 30, 2006 firefighters work inside the car park of Terminal 4 of Barajas Airport in Madrid after a bomb by armed Basque separatist group ETA exploded, killing two people

Key dates in the history of the armed Basque separatist movement ETA, which announced it had fully disbanded in a letter published on Wednesday.

- Fight against dictatorship -

- July 31, 1959: ETA (Euskadi Ta Askatasuna) is formed during the dictatorship of General Francisco Franco by a group of Basque nationalist students.

- June 7, 1968: ETA shoots dead the police chief of the Basque city of San Sebastian -- the first deadly attack for which it claimed responsibility.

Over four decades ETA will be blamed for at least 829 deaths.

- December 20, 1973: Luis Carrero Blanco, Franco's prime minister and presumed successor, is blown up in his car in Madrid -- one of ETA's most notorious attacks.

- Paramilitary death squads -

- October 15, 1977: Two years after Franco's death, a general amnesty for political prisoners, including from ETA, is declared by Spain's first post-Franco democratic government.

- October 25, 1979: The Basque region is granted autonomous status.

- 1980: ETA's most deadly year, with at least 92 people killed in attacks.

- December 1983: Emergence of GAL, a paramilitary group which kills 28 Basque militants through 1987.

- June 19, 1987: ETA stages its deadliest bombing, killing 21 shoppers at a Barcelona supermarket car park.

- July 12, 1997: ETA shoots a conservative town councillor in the Basque country who dies of his wounds the next day. Millions take to the streets in protest.

- Broken ceasefires -

- September 16, 1998: ETA announces a unilateral and unlimited ceasefire, which it goes back on in late 1999 after the failure of talks with the government.

- March 17, 2003: Batasuna, ETA's political wing created in 1978, is outlawed.

- March 22, 2006: ETA declares a "permanent ceasefire" in return for talks with the government.

- December 30, 2006: ETA claims responsibility for a bombing at Madrid airport that kills two people, breaking the ceasefire. ETA carries out seven more attacks by summer 2009.

- November 17, 2008: ETA's military chief Garikoitz Aspiazu Rubina is arrested in France. His five successors are arrested in turn.

- August 9, 2009: ETA carries out its last attacks on Spanish soil. Its last victim is a French policeman killed during a chase in the Paris region in March 2010.

- End of armed struggle -

- October 20, 2011: ETA announces "the definitive end to its armed activity", but declines to formally disband or disarm. A month later the leftist separatist coalition Amaiur, an offshoot of Batasuna, gains seats in the Spanish parliament.

- November 24, 2012: ETA says it may discuss disbanding if jailed members are moved to prisons nearer home. Spain refuses to negotiate.

- April 8, 2017: ETA announces its "total disarmament" and begins surrendering weapons to the French authorities.

- Dissolution -

- February 22, 2018: ETA starts to vote on its dissolution, the Basque daily Gara reports.

- April 20, 2018 - ETA apologises for the "pain" and "harm" it caused during its armed campaign. It asks for forgiveness from some of its victims -- those "not involved in the conflict".

- May 2, 2018: Spanish media publish a letter sent by ETA to groups involved in peace efforts, in which the group announces its full dissolution. A further direct declaration is expected in the coming days.