Source: Telegraph

The concerns have been triggered by Bosnian Serb leaders who have stepped up their demands for independence with a warning the country is no longer "sustainable".

The growing ethnic divisions have raised fears of a return to the fighting which claimed the lives of up to 110,000 people between 1992 and 1995.

Senior European and US officials have called an emergency meeting in Sarajevo on Tuesday to meet the country's leaders to find a solution.

The crisis centres on attempts to overhaul the constitution which was imposed on the country in 1995 in the wake of the war.

Since then Bosnia has been made up of two semi-independent entities – the Serbs' Republika Srpska and the Muslim-Croat Federation.

The two are linked with weak central institutions whose functioning is often obstructed by ethnic rivalries.

Serb groups claim attempts to streamline the complex government system are designed to undermine their position and absorb them into stronger central state.

Milorad Dodik, the Bosnian Serb prime minister, has described constitutional changes as "unnecessary and unacceptable".

"Bosnia is an unsustainable country ... the international community has overplayed its hand in Bosnia, and this will become evident in the end," he said.

Mr Dodik has called for referendum on self-determination to be included in the constitution that could pave the way for Republika Srpska's independence from Bosnia.

Sulejman Tihic, the leader of Bosnia's largest Bosnian Muslim party, said he fears that a new war could be looming.

"If it continues to go on like this, there is no question there will be conflict. It's just a question of what kind of conflict there will be, and is it going to be in three months, six months or one year?," he said.

Lord Ashdown, who served as the international community's High Representative in Bosnia from 2002 until 2006, has also sounded the alarm.

"This is a crucial moment and if the international community fails to address it, Bosnia risks slipping towards disintegration," he said.

Jim Steinberg, the US deputy secretary of state, will fly to Sarajevo on Tuesday for talks aimed at breaking the deadlock, along with Carl Bildt, the Swedish foreign minister, and Olli Rehn, the European Commissioner for Enlargement.

Mr Rehn said on Wednesday: "This political stalemate has dragged this country backwards.

"I hope that Bosnian leaders will rise to the occasion for the sake of their citizens and for the sake of the Western Balkans and Europe as a whole."

Brussels is holding out the prospect of EU membership as an incentive for constitutional reforms.

"We are aiming at agreeing certain constitutional changes that will make Bosnia-Herzegovina a functional state and able to be considered as candidate country for the EU. We want Bosnia Hercegovina to be a credible applicant for EU and Nato membership.

"But for this to happen the country needs to stand on its own feet without the OHR [High Representative] and its broad executive powers. No quasi-protectorate can join the EU."

Bosnia-Hercegovina is still recovering from the devastating three-year war which followed the break-up of Yugoslavia in the early 1990s.

The conflict centred on whether Bosnia should stay in the Yugoslav Federation, or whether it should become independent.

The war left Bosnia's infrastructure and economy in tatters. Around two million people – about half the population – were displaced.