(Reuters) - Suspected Tamil Tiger rebels bombed a bus in central Sri Lanka on Saturday killing at least 20 people, the military said.
Here is a chronology of major attacks blamed on the Liberation Tigers of Tamil Eelam (LTTE), fighting for an independent state since 1983:
April 1987 - Car bomb explodes at Colombo central bus station, killing 113 people and wounding scores.
April 1989 - Car bomb explodes in the eastern port of Trincomalee, killing 51 people shopping for traditional new year.
March 1991: Defense Minister Ranjan Wijeratne is among 19 killed when a car bomb is detonated in Colombo.
May 1991 - Former Indian prime minister Rajiv Gandhi is killed in southern India by a suspected LTTE suicide bomber.
August 1992 - The army chief, Lieutenant-General Denzil Kobbekaduwa, is killed in a landmine blast in Kayts, in northern Sri Lanka.
November 1992 - Navy chief Clancey Fernando is killed in a suicide bombing in Colombo.
May 1993 - President Ranasinghe Premadasa and 23 others are killed by a suicide bomber in Colombo.
October 1994 - Presidential candidate Gamini Dissanayake is one of 52 killed in a bomb blast at a Colombo election rally.
January 1996 - A truck filled with explosives rams into the Central Bank building in Colombo, killing up to 100 people and wounding 1,400.
July 1996 - Two bomb blasts on a rush-hour commuter train kill 57 people and wound more than 250.
December 1999 - President Chandrika Kumaratunga is wounded in an attempted assassination by a suicide bomber; at least 34 are killed in two explosions. She lost an eye.
June 2000 - Industrial Development Minister C.V. Gunaratne and 21 others are killed in a suicide bomb blast in Colombo.
July 2001 - Attack on main air base and only international airport kills at least 12 people and destroys 13 aircraft.
August 2005 - Foreign Minister Lakshman Kadirgamar is shot dead at his home in Colombo.
April 2006 - Army Commander Major General Sarath Fonseka is badly hurt in an abortive suicide attack on Army HQ in Colombo.
May 2006 - Kethesh Loganathan, deputy head of peace secretariat, is shot dead by a suspected rebel at his Colombo home.
June 2006 - Army Deputy Chief of Staff Parami Kulatunga killed as suicide bomber rams a motorcycle laden with explosives into his vehicle outside Colombo.
June 2006 - A mine attack on a civilian bus in the central district of Anuradapura kills 64.
October 2006 - Nearly 100 people, mostly navy sailors, are killed in a suicide bombing on a convoy near the town of Habarana, northeast of Colombo.
January 1, 2008 - Main opposition United National Party (UNP) parliamentarian T. Maheshweran is shot dead at a Hindu temple in Colombo. Government blames the rebels, but the opposition blames the government.
January 8, 2008 - Nation Building Minister D.M. Dassanayake is killed by a roadside bomb planted by suspected Tamil Tiger rebels in the town of Ja-Ela, 12 miles north of Colombo.
January 16, 2008 - Suspected Tiger rebels bomb civilian bus in central district of Moneragala, killing 24 people and wounding dozens on the day a 2002 ceasefire formally expires.
February 2, 2008 - Bomb explodes on civilian bus in central town of Dambulla, killing at least 20 people and wounding 50. Military blames attack on Tamil Tigers.
Writing by Nagesh Narayana; Editing by Jeremy Laurence