TIMELINE: Sri Lanka's 25-year civil war

(Reuters) - Sri Lanka's Tamil Tiger rebels declared a unilateral ceasefire on Sunday, with the military having surrounded them in a tiny area along with thousands of civilians. The move was immediately rejected by the government.

Following are some key events in the 25-year conflict between Tamil separatist rebels and the government in Sri Lanka.

1983 - Tiger attack in north kills 13 soldiers, triggering anti-Tamil riots in capital, Colombo. Hundreds die, thousands flee. Start of what Tigers call "First Eelam War."

1987 - Having earlier armed Tigers, India sends troops to enforce truce it brokered. Tigers renege, refuse to disarm and begin three years of fighting that kills 1,000 Indian soldiers.

1990 - India withdraws. LTTE controls northern city of Jaffna. "Second Eelam War" begins.

1991 - Suspected Tiger suicide bomber kills former Indian Prime Minister Rajiv Gandhi in southern India. Two years later, Sri Lankan President Ranasinghe Premadasa assassinated in separate suicide attack. LTTE blamed in both.

1995 - President Chandrika Kumaratunga agrees to truce with rebels. "Eelam War 3" begins when rebels sink naval craft. Tigers lose Jaffna to government forces.

1995-2001 - War rages across north and east. Suicide attack on central bank in Colombo kills around 100. Kumaratunga wounded in another attack.

2002 - Landmark ceasefire signed after Norwegian mediation.