Sri Lanka’s Tamil Tiger rebels are being urged to consider surrendering to advancing government troops. International mediators to the country – the US, the European Union, Japan and Norway – say further civilian deaths in the conflict must be avoided.Thousands are trapped in a war zone in the north, where the army claims the rebels are surrounded. The government says it is confident it will soon win the conflict, which has killed more than 70,000 people since the early 1980s. Soldiers say they have captured an underground bunker they claim has recently been used by the leader of the Tamil Tigers. The Western mediators say it will probably not be long before the rebels completely lose control of their strongholds. The Norwegian Aid and Development Minister, Erik Solheim, said: “The Tamil Tigers are unlikely to return as a conventional army. There should be a transition to a political struggle for the same goals, namely better self rule for the Tamil minority in Sri Lanka.” Independent reports from the conflict zone are not available because journalists are banned from the area. But aid workers say at least 12 people have been killed in a hospital that has been shelled for a fifth time in three days.