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KONJIC, Bosnia (Reuters) - A convoy of buses carrying 270 migrants in Bosnia to a refugee center was held up for hours on Friday in a standoff that exposed frictions between regional and national authorities in the multi-ethnic Balkan state.

Armed police in a southern, Croat-dominated canton had turned back the convoy without explanation, surprising state migration officers escorting the migrants who had been moved from a Sarajevo park where they had camped for nearly two months.

The incident reflects tension over how to deal with more than 4,000 migrants who have entered the country this year from Syria, Iraq, Turkey, Algeria and Afghanistan after people smugglers created a route from Greece via Bosnia to EU member Croatia and western Europe.

The buses turned to head back to the Sarajevo canton, dominated by Muslim Bosniaks, whose special police forces arrived at the scene to secure the migrants.

The two separate police forces were stationed at opposite ends of a tunnel, which is regarded as a border line between them, in the situation described as tense and confusing by the officials. Some migrants panicked they would be deported, with some fainting and needing medical aid, a Reuters witness said.

The central government in Sarajevo, which links Bosnia’s two autonomous regions created after the country’s war in the 1990s - the Bosniak-Croat Federation and the Serb Republic - has jurisdiction over migrants and decided to move the people who were sleeping rough in the capital into safer accommodation.

But the government of the Herzegovina-Neretva canton, one of 10 cantons in the Federation, said they were not informed about the decision and that arrival of migrants could ‘destabilize’ their region.

Bosnia’s Security Minister Dragan Mektic said the cantonal police had violated the Bosnian constitution and laws by preventing state officials from performing their duties and said the prosecutors would deal with the offences.

But soon after Mektic addressed reporters in the town of Banja Luka, the police in the Croat-dominated canton let the buses pass and escorted them to a refugee center in Salakovac, some 100 kilometres (62 miles) south of Sarajevo, where the passengers were accommodated and given meals.