WASHINGTON - TWO senior US Senators on Monday jointly urged Sri Lanka's government and Tamil Tiger rebels to safeguard civilians and ease humanitarian access to areas affected by the deadly conflict.

Democrat John Kerry, chairman of the Senate Foreign Relations Committee, and Republican Richard Lugar, the panel's top Republican, said they were 'greatly concerned about the deteriorating humanitarian situation.'

'We urge the Government of Sri Lanka and the Liberation Tigers of Tamil Eelam to immediately take all necessary steps to protect civilians and facilitate humanitarian access,' the lawmakers said in a joint statement.

Mr Kerry and Mr Lugar said they were 'deeply troubled' by the government's recent threats to expel aid agencies, diplomats and foreign journalists seen as supportive of Tamil rebels.

Sri Lanka does not allow independent media free access to the island's conflict zone and to the camps housing those displaced civilians who have managed to flee the fighting.

'Reporters have already experienced physical attacks and intimidation, including the latest brazen assassination of renowned journalist Lasantha Wickrematunga,' Mr Kerry and Mr Lugar said.

'Together, we urge the government of Sri Lanka to protect all of its citizens and conduct swift, full, and credible investigations into attacks on journalists and other civilians.'

The government maintains that it has a policy of 'zero civilian casualties' and accuses the Tamil Tigers of using tens of thousands of men, women and children as a human shield.

Since the Jan 8 killing of Mr Wickrematunga, who was editor of the anti-war Sunday Leader, at least eight senior journalists and media activists have fled the island, fearing that they too could be targeted by unidentified attackers. -- AFP