Sri Lanka on Monday gave the Liberation Tigers of Tamil Eelam (LTTE) rebels 24 hours to surrender after thousands of civilians fled the war zone when troops breached a fortification blocking their exit, the military said.
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.
2003 - Tigers pull out of peace talks, ceasefire holds.
2004-2005 - Tamil Tiger eastern commander Colonel Karuna Amman breaks away from LTTE and takes 6,000 fighters with him Suspected Tiger assassin kills foreign minister. Anti-Tiger hard-liner Mahinda Rajapaksa wins presidency.
2006 - Fighting flares in April-July, raising fears of start of "Eelam War 4." New talks fail in Geneva in October.
2007 - Government captures Tiger's eastern strongholds.
2008 - Government annuls ceasefire in early January and launches massive offensive.
January 2, 2009 - Troops seize Tiger's defacto capital, Kilinochchi.
April 5 - Military says it has confined the rebels to a no-fire zone measuring just 17 square km (6.5 sq miles).
April 17 - Rebels call for a truce after two-day government fighting pause expires. Government rejects the call as a ruse.
April 20 - Sri Lanka gives the rebels 24 hours to surrender.
(Writing by Rob Dawson, Gillian Murdoch and Jijo Jacob; Additional writing and editing by David Cutler, London Editorial Reference Unit; Editing by Jerry Norton)