Political instability is damaging Bosnia's prospects of joining the EU and causing some officials to worry that the Balkan country could one day slide back into conflict.

The former Yugoslav republic, which was divided into a Serb Republic and a Muslim-Croat entity after the 1992-95 Bosnian war that killed about 100,000 people, is run by a weak central government and some Serbs favour secession.

Ethnic quarrels were among problems identified by the EU last week in its annual report on Bosnia's progress towards membership of the wealthy bloc.

Political tensions are now running so high that some regional experts and leaders say violence could eventually flare again in the country of about four million people.

"There could be war," said Sulejman Tihic, the head of Bosnia's largest Muslim political party and former Muslim member of the tripartite Presidency. "A year or two ago I would not have said this is possible."

The Democratisation Policy Council, a non-profit group, said in a report last week that renewed conflict was possible and added: "Bosnia has not only stagnated over the past three years - it has been sliding backwards at an accelerating pace."

Tension has mounted over moves taken by Bosnian Serb Prime Minister Milorad Dodik independently of the central government in Sarajevo, saying he seeks economic prosperity and eventual EU membership for his people.

Some experts fear Bosnian Muslims might hit back militarily if the Serb Republic's push for state-like powers goes out of control.

"War is not going to break out tomorrow, but if this is allowed to continue, it may break out a year from now, or two years from now, or four years from now," said a foreign diplomat with years of experience of the region. Other experts do not expect renewed conflict, even if tensions are high.

Ruling out a return to violence, Haris Silajdzic, the Muslim member of Bosnia's tripartite presidency, said: "It is not dangerous ... It is a quite different situation today (to before the Bosnian war)."

The EU's executive Commission said in its latest report on Bosnia that progress on EU-related reforms had stagnated amid disputes among ethnic leaders.