Hundreds more Tamil civilians have fled Sri Lanka's war zone, the defence ministry said on Friday, as Colombo angrily rejected Britain's appointment of a special envoy to the island.
Men, woman and children crossed the front lines in the district of Mullaittivu where the army has cornered the remaining forces of the rebel Liberation Tigers of Tamil Eelam (LTTE).
"The people fled despite a series of barricades imposed by the LTTE to stall the civilian influx," the ministry said in a statement.
The government has accused the Tiger rebels of using civilians trapped by the fighting as "human shields" and of preventing them from leaving the area. The Red Cross says hundreds of non-combatants have already been killed.
The latest flight of civilians came as Britain said it had appointed former defence minister Des Browne as a special envoy to focus on the humanitarian situation in Sri Lanka.
The move by the former colonial power was swiftly condemned by the government in Colombo.
"It is tantamount to an intrusion into Sri Lanka's internal affairs and is disrespectful to the country's statehood," Foreign Minister Rohitha Bogollagama told AFP.
The minister warned of "major repercussions" for relations with Britain.
"There is no further discussion with London on the matter," Bogollagama said, after the British Foreign Office had said talks were ongoing to resolve the dispute.
British Prime Minister Gordon Brown's office said Browne, who left office last October, would work with all sides.
The Colombo government says it is on the brink of crushing the rebels and has resisted international calls to halt its offensive against the Tigers, who have fought since 1972 for the creation of an independent Tamil homeland.
On Thursday, Sri Lanka set up a new safe zone for non-combatants along a 12-kilometre (7.5-mile) stretch of coastline, effectively scrapping a smaller designated no-fire area.