COLOMBO - The foreign ministers of Britain and France urged Sri Lanka on Wednesday to implement a humanitarian ceasefire with Tamil Tiger rebels in order to allow tens of thousands of trapped civilians to escape the battle zone.

They also urged the rebels to allow the civilians to leave.

The civilians, estimated by the United Nations to number as many as 50,000, are caught in a tiny area less than 10 square km (4 sq miles) on Sri Lanka's northeast coast.

It is the last redoubt of the Liberation Tigers of Tamil Eelam (LTTE), who have been fighting a 25-year war with the government for a separate ethnic Tamil homeland.

Protection of civilians is absolutely paramount at this moment. The LTTE must end preventing civilians leaving the conflict zone and the fighting must stop, British Foreign Secretary David Miliband told reporters.

His comments were in line with a European Union call earlier this week for a ceasefire, a position widely taken by the international community but so far resisted by Sri Lanka.

Although the government says it has stopped regular combat operations using heavy weapons and is concentrating only on freeing trapped civilians, it fears a complete ceasefire would give the Tigers space to rearm and regroup.

Miliband denied international calls for a ceasefire had anything to do with trying to help the Tigers.

No one in the international community has been calling for a ceasefire or to stop firing to save (Tiger leader Vellupillai) Prabhakaran. The calls have come because of the overwhelming concern with the well-being of the civilians.

The Tigers say the government claim to have ended heavy weapons use is a sham, and that artillery and air strikes continue to cause scores of civilian deaths, charges the military denies.

At the same time the military says what it calls its civilian rescue efforts, using small arms, are bringing serious casualties among the Tigers.

A statement on the army's website on Wednesday said that in fighting with the Tigers the previous day troops inflicted heavy damages to terrorists killing over 35 fighting cadres.

SUICIDE BOATS

Navy spokesman Captain D.K.P Dassanayake said separately that on Wednesday, navy forces engaged with a cluster of LTTE suicide and attack boats and destroyed six ... killing 25 Sea Tigers.

Checking claims from the battle zone, where 50,000 troops surround an estimated few hundred to few thousand remaining rebel fighters among far more civilians, is difficult given lack of access and of independent sources on the ground.

While both sides say they avoid targeting civilians, an internal U.N. tally of casualties says nearly 6,500 people have been killed in fighting since late January.

Miliband and French Foreign Minister Bernard Kouchner, who also want Sri Lanka to provide access to the conflict zone for the United Nations and aid agencies, were speaking after meeting government officials and ahead of a visit to camps for the close to 200,000 who have already escaped the fighting.

Asked about the government response to their requests, Kouchner said: We insisted, and we insisted, but it is up to our friends to allow it or not.

Aid from the European Union and other foreign donors is important to Sri Lanka economically, as are foreign markets for its commodities like tea and products like textiles.

The conventional war's end would leave Sri Lanka facing the challenges of healing years of division and boosting an economy beset by a declining currency, falling exports of tea and garments and low foreign exchange reserves.

It seeks a $1.9 billion International Monetary Fund loan and business executives are optimistic the war's finish would bring foreign investment back, but the LTTE has warned it will stage guerrilla attacks on economic targets as it has done before.

Although President Mahinda Rajapaksa's government -- which has pursued an unrelenting military offensive against the LTTE since early last year -- has come under fire from many in the international community as too hardline, that approach has won wide support among Sri Lanka's ethnic Sinhalese majority.

Conversely, the government's announcement this week it would stop using heavy weapons and suspend regular combat operations has been attacked by opposition politicians as a sign of weakness in the face of international criticism.

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