top U.S official has called for unifying Bosnian government institutions that have remained divided on ethnic lines since the 1995 Dayton Peace Agreement halted the conflict in the country.

U.S. Undersecretary of State for Political Affairs Nicholas Burns told reporters in Sarajevo the Dayton agreement has served its purpose and the time has come to transform Bosnia-Herzegovina into a unitary state. He urged major constitutional reforms that would lead to creation of a single Bosnian presidency, a stronger government and an effective parliament.

The Dayton Agreement left Bosnia with a collective presidency, made up of Croat, Muslim and Serb members and divided the country into a Serb Republic and Muslim-Croat Federation. Each has its own administration and parliament under a weak central government.

Sarajevo is the first stop of Mr. Burns' Balkan trip, which also will take him to Pristina and Belgrade.

Some information for this report provided by AFP, Reuters and AP.