BEIJING, March 12 (Xinhuanet) -- Two simultaneous bomb explosions ripped through four commuter trains in Spain on Thursday morning and killed at least 192, marking the deadliest terror attacks in Spanish history.

    Government's initial conclusion pointed to the underground Basque separatist group ETA, or Basque Homeland and Freedom founded in 1959.

    With the aim of establishing independent homeland in Spain's Basque region and the southwestern French provinces of Labourd, Basse-Navarra and Soule, ETA has resorted to assassination, kidnapping and bombing.

    The following is a chronology of key attacks staged by the group within the two decades.

    1980 -- Nearly 100 people were killed across the country in a single year.

    September 1985 -- A car bomb killed an American and wounded 16 policemen in Madrid.

    April 1986 -- Five civil guard policemen died in a car bombing in Madrid.

    July 1986 -- 12 civil guards were killed in a car bombing and 50 wounded in Madrid.

    June 1987 -- 21 people were killed in a car bombing in a Barcelona supermarket.

    December 1987 -- A car bomb killed 11 in northeastern Zaragoza,including five children.

    December 1991 -- Ten, including four children, were killed in acar bomb attack in northeastern Vic.

    February 1992 -- A car bomb in Madrid killed five.

    June 1993 -- A car bomb in Madrid killed six servicemen and a worker in Defense Ministry.

    April 1995 -- Jose Maria Aznar, then the opposition leader and present prime minister of Spain, escaped an assassination bomb attack in Madrid.

    August 1995 -- King Juan Carlos became the target of assassination plot and survived after police foiled the attempt.

    December 1995 -- A car bomb killed six in Madrid.

    February 1996 -- Former head of Spain's constitutional court Francisco Tomas y Valiente was killed in Madrid.

    July 1997 -- Basque town councilor Miguel Angel Blanco was kidnapped and shot dead.

    February 2000 -- Vitoria socialist politician Fernando Buesa was killed in a car bombing along with his bodyguard.

    November 2000 -- Former socialist health minister Ernest Lluch was shot dead in Barcelona.

    February 2001 -- Two were killed in a car explosion and four wounded in San Sebastian.

    November 2001 -- A car explosion injured 95 in Madrid, and two policemen were killed later in southern San Sebastian.

    June 2002 -- Seven were wounded in three car explosions in Fuengirola, Marbella and Zaragoza ahead of an EU summit. Enditem