Troops gear up for Bosnia arrests

British troops are reported to be strengthening the helicopter landing site at Bihac in north-west Bosnia to take Black Hawk helicopters like those used in Thursday's operation to seize two Bosnian Serbs indicted for war crimes. The move suggests more such operations in north-west Bosnia may be imminent.

As speculation grew that S-For peacekeepers were about to arrest the biggest fish - Radovan Karadzic and Ratko Mladic - military sources stressed the special nature of Thursday's operation to catch Simo Drljaca and Milan Kovacevic: "These guys were moving around completely openly in the British sector."

Mladic and Karadzic are believed to be near Pale, east of Sarajevo, in the French sector. "It's a very difficult, very different operation," a senior British officer said. "The key [to Thursday] was a sealed indictment, so we could pick the best time to get them."

No one except for Louise Arbour, the chief prosecutor of UN war crimes in the Hague tribunal, knows the exact number of suspects on the sealed list.

"It is thought there were nine - of which three have been enforced," said Chris Bennett, of the International Crisis Group, in Sarajevo. "So, there are six to go."

The first sealed indictment was for Slavko Dokmanovic, the Serb mayor of Vukovar in Croatia who was arrested by the UN on 27 June. Thursday saw British troops snatch Kovacevic and Drljaca, who was killed when he opened fire.

Heading the list of the "six to go" are almost certainly Zeljko Raznjatovic "Arkan", the Belgrade-based paramilitary chief who "cleansed" Bijeljina in north-east Bosnia in April 1992, and Velibor Ostojic, a close colleague of former Bosnian Serb leader Radovan Karadzic, who organised the cleansing of Foca, in eastern Bosnia, a few weeks later. Ostojic is deputy prime minister of the Republika Srpska, the Bosnian Serb state.

Sources in Bosnia believe one surprise factor will be the presence of Muslims and Croats on the sealed list, most probably Ramiz Delalic "Celo", the muslim hoodlum accused of killing numbers of Serb civilians while organising the defence of Sarajevo, and Mladen Naletilic and Vinko Martinovic, two Bosnian Croats who "cleansed" Mostar, in southern Bosnia, of its Muslims.

Why high-ranking, well known suspect killers were left off the UN-published list of 74, of whom 66 are at large, is no mystery. "The worst atrocities took place in the towns of Brcko, Srebrenica, Visegrad, Zvornik and Bijeljina," said Srdjan Dizdarevic of the Helsinki Committee in Sarajevo.

"Some of these towns are still in Republika Srpska, so there is no one to dig up the mass graves and see how many victims there were."

Mr Dizdarevic fears there will be no move to seize suspects of higher rank than Drljaca. "They don't want to go up to the level of [Serbian President Slobodan] Milosevic. It was the price of getting them to sign the Dayton agreement."

Amnesty International yesterday warned that with only 11 months before S-For mandate in Bosnia expires, the big powers need to act fast: "There needs to be more than one arrest a week to ensure merely the current publicised indictees are in custody by the end of the S-For mandate."