PUTTUMATALAN, Sri Lanka – Indian envoys flew into Sri Lanka on Friday to urge a truce in the closing chapter of a 25-year war in which U.N. data showed nearly 6,500 civilians have been killed in the last three months.

A few kilometers (miles) from the front, thousands of refugees languished in the blazing tropical sun awaiting transport away from the battlezone, where the army is trying to deal a death blow to the Liberation Tigers of Tamil Eelam (LTTE).

Explosions boomed and smoke billowed from the remaining battlefield, formerly an army-declared no-fire zone but now all that remains of the self-declared state the LTTE has fought since the early 1970s to create for Sri Lanka's minority Tamils.

We are clearing mines and other entrapments. The progress has almost stopped because we have come across these things, 58th Army Division commander Brigadier Shavendra Silva told Reuters in Puttumatalan, on the northeastern coast.

The military said that more than 108,000 people have poured out of the war zone since Monday, when troops blasted through an earthen barrier the LTTE had built to block movement in or out of their dwindling territory.

Diplomatic pressure over the war has boiled over this week with the U.N. Security Council, the United States and others demanding Sri Lanka stop its offensive and the LTTE surrender to avert rising civilian casualties.

A U.N. working document, a copy of which was obtained by Reuters, says 6,432 civilians have been killed and 13,946 have been wounded in fighting since the end of January. Two diplomats verified its authenticity. A U.N. spokesman declined to comment.

Both sides accuse the other of firing on civilians. With access to the war zone limited to most outsiders and nearly all sources inside lacking full independence, getting clear data is difficult.

Sri Lanka is reluctant to allow outsiders in, with the memory of India intervening when it had the Tigers on the ropes in 1986 still fresh.

However, Indian Foreign Secretary Shivshankar Menon and National Security Adviser M.K Narayanan flew into Colombo on Friday for a meeting with President Mahinda Rajapaksa, Sri Lankan officials at the foreign ministry and president's office said. It was a swift reversal by India's Congress party-led ruling coalition, which backs efforts to wipe out a group India lists as a terrorist organization but faces election pressure in the Tamil-majority southern state of Tamil Nadu to protect civilians.

Separately, the Sri Lankan government rejected a plan by U.N. Secretary-General Ban Ki-Moon on Thursday to send a humanitarian team to assess the condition of people trapped by the fighting.

Foreign Secretary Palita Kohona told reporters a humanitarian mission was discussed some time ago, but now that there had been an exodus of people, there was no need for it.

As these statements were made based on reports prior to the sudden influx of civilians from there, the need of the visit may not arise anymore, Kohona said.

CIVILIAN THRONGS

The military has cornered the separatists in less than 13 square km (5 square miles) of the northeastern coastline, where the United Nations says 50,000 people are being held as human shields and suffering with little food, water or medical care.

Silva told reporters: The LTTE is firing artillery into their own area to make it look like the government is firing artillery.

He said intelligence had intercepted LTTE leaders ordering its fighters to trade their trademark tiger-stripe camouflage fatigues for civilian garb. The guerrilla LTTE has hidden among civilians since they began fighting in the 1970s.

The Tigers could not be reached for immediate comment, but they routinely deny attacking people despite numerous witness accounts they have shot at those trying to escape their area.

The LTTE has vowed no surrender and Sri Lanka has ruled out any further humanitarian pauses, wary that the Tigers may use it to rearm as it has in the past.

Journalists saw thousands of people in the coastal village of Puttumatalan during a military-chaperoned trip on Friday. Belongings were strewn all over the main A-35 road, discarded in the haste to escape the LTTE-held area. Soldiers gave people food and water, while a group of about 50 people bathed in a ditch.

Diplomats said they were frustrated by intransigence on both sides, but that Colombo would be the focus of more pressure since it was a sovereign country and there was no leverage with the LTTE now that they are near a conventional defeat.

This whole thing is now moving to a new level. You have a lot of things coming together at one time, and the numbers are climbing and cannot be ignored, said a Western diplomat, speaking on condition of anonymity.

India