Tamil Tigers 'encircled'
Since Monday, the government has said that 104,862 civilians have escaped the conflict between the Sinhalese who are in power and the Tamil minority who say they are being marginalised.
David Chater, Al Jazeera's correspondent near Kilinochchi in the north, said: "The army are pushing to encircle the remaining Tamil Tigers ... moving along the beaches to separate them from the ocean.
"We know that 103,000 Tamils have been processed through all the checkpoints and sent to IDP [Internally Displaced Person] camps."
Civilian casualties have been rising in the conflict zone where the military has been trying to finish off the armed rebellion, according to Doctors Without Borders.
People with untreated blast, mine and gunshot wounds are reported to be among more than 100,000 civilians pouring out of the war zone.
India has joined the UN in dispatching teams to Sri Lanka to help deal with what the two have described as a "rapidly deteriorating situation".
"So many lives have been sacrificed. There is no time to lose," Ban said.
"The purpose of this humanitarian team would be to, first of all, monitor the situation and support humanitarian assistance and try to do whatever we can to protect the civilian population," he said, urging the government to co-operate.
|The UN estimates 50,000 are still trapped
in the war zone [Reuters]
The army said LTTE fighters were ignoring calls to surrender and putting up stiff resistance despite being cornered into an area smaller than 12 sq km on the northeast coast.
India, which has been blamed by Tamils for aiding the Sri Lankan government's efforts against the LTTE, has called for an "immediate cessation of all hostilities".
Pranab Mukherjee, the Indian foreign minister, expressed "deep concern and anxiety" for "the conditions of Tamil civilians in the conflict zones".
The country's 25-year civil war has flared in recent months with the Sri Lankan military pushing to crush the Liberation Tigers of Tamil Eelam (LTTE) rebels in their remaining territory in the north.
The Sri Lankan army blames the LTTE for trapping about 15,000 to 20,000 civilians, and said their surrender was the only way they could be freed.