Sri Lanka gave Tamil Tiger fighters and their leader 24 hours to surrender after tens of thousands of trapped civilians managed to flee on Monday from the last area under rebel control.
The deadline for Tigers supremo Velupillai Prabhakaran and his guerrillas would run out at midday Tuesday, said defence ministry spokesman Keheliya Rambukwella.
"We warn Prabhakaran and his cadres to surrender within the next 24 hours," he told reporters, without specifying what action would be taken if the ultimatum was ignored by the Liberation Tigers of Tamil Eelam (LTTE).
The warning came as aerial video footage provided by a Sri Lankan spy plane showed more than 35,000 civilians pouring out of the sliver of jungle territory where the LTTE are making their final stand in the northeast of the island.
The presence of the civilians has been cited by the Sri Lankan military as one of the main reasons preventing a final, all-out assault on the remaining Tigers holed up in a government designated "no-fire zone."
President Mahinda Rajapakse said the rebels' were facing "complete defeat" and that their reclusive leader had finally run out of time.
"The only thing Prabhakaran can now do is to surrender," the president said. "I don't want him to take cyanide and commit suicide. He has to face charges for his actions."
The government had issued several similar ultimatums in the past -- most recently on April 12 when the guerrillas were told they had 48 hours to give themselves up.
Rajapakse's office in a statement issued on Monday evening compared the exodus of civilians to the fall of the Berlin Wall.
"The exodus to freedom that is taking place in the north of Sri Lanka just now, is no less a massive vote for freedom than the fall of the Berlin Wall in November 1989," the statement said.
The only reaction from the Tigers was to renew their call for an unconditional ceasefire. The government has already rejected any possibility of a truce.
U.N. Secretary General Ban Ki-moon welcomed the civilians' escape but remained "deeply concerned" about those still trapped in the conflict zone, his press office said in a statement.
According to the U.N., as many as 100,000 civilians were trapped in LTTE territory and living in "dire humanitarian conditions" before Monday's exodus.
The mass civilian escape shown in the aerial footage appeared to have been triggered by the Sri Lankan military overrunning a Tiger defensive embankment in the early hours of Monday morning.
"The footage clearly shows that the people are defying the LTTE and escaping. They are running to safety," President Rajapakse said.
"What we are doing is not a military operation, but the world's biggest hostage rescue."
The government has accused the LTTE of using trapped civilians as a human shield, and the president implied that their escape removed a final obstacle to a military assault.
"The process of the complete defeat of the LTTE has just begun," he said. "It is now all over for the Tigers."
The Sri Lankan defense ministry said the Tigers killed 17 civilians Monday in at least one suicide bombing that targeted the escaping civilians.
Air Force chief Roshan Goonetileke said the rebels had tried to stop them by shooting and setting off explosions, but the sheer size of the sudden exodus had appeared to overwhelm the Tigers.
Both sides in the long-running conflict have traded accusations of targeting non-combatants, while the international community has repeatedly urged a permanent ceasefire to prevent any further loss of innocent lives.
The LTTE were once seen as one of the world's most efficient guerrilla outfits, controlling a third of Sri Lanka's territory, an overseas fund-raising network and a lucrative shipping business.
But now the rebels are outnumbered and surrounded in the jungles outside Mullaittivu, their former military headquarters in the northeast.
Defeat would end the Tigers' 37-year campaign for a Tamil homeland within the Sinhalese-majority island.© Wire reports