MOSTAR, Bosnia-Herzegovina (AP) _ Hundreds of Bosnians expelled from their homes in Muslim-Croat fighting crossed to the other side of divided Mostar to vote Sunday in Bosnia's first postwar election.

The municipal election in this medieval valley town, which straddles a river separating Muslim east from Croat west, is a crucial test for the Dayton peace accord.

The atmosphere in some places was hostile, but there were no reports of violence Sunday.

Across from the polling station where Muslims were voting in Croat-held west Mostar, a Croat cafe owner blasted anthems of the Ustasha, the Croatian Nazi puppet regime that controlled much of Bosnia during World War II.

A group of 135 Serb refugees returning on Saturday night for the election ran a gauntlet of hostile Muslims as they got off their buses in the Muslim east. Police arrested three Muslims in the scuffle.

Western officials said the relative peace on election day was a good sign, and the European Union administrator for Mostar, Ricardo Perez Cassado, called the election a ``success.''

``This is a very important and significant precedent for the elections we're planning for September nationwide,'' U.S. Ambassador John Menzies said. ``It shows that people are engaged in this process.''

Officials said turnout was near 70 percent in some areas, much higher than the 40 percent they had expected. First unofficial results were expected on Monday.

Last year's peace accord provides for a Muslim-Croat federation to rule Bosnia in a loose confederation with a Bosnian Serb substate. The Mostar vote will gauge the success of international attempts to foster Muslim-Croat unity nationwide.

The separatist Croatian Democratic Union has indicated it would consider a sweep of all 16 city council seats set aside for Croats as a mandate for continued division. Sixteen other seats are for Muslims, five for Serbs.

Much of the 3 1/2-year war that devastated Bosnia was fought between Croats and Muslims on the one side and rebel Serbs on the other; but in the spring of 1993, Muslims and Croats turned on each other. The United States forced a Muslim-Croat truce and federation agreement in March 1994.

Deep divisions remain, most evidently in Mostar, the southern town that separatist Croats named capital of their self-styled republic in Bosnia, Herceg-Bosna.

The European Union, which has administered Mostar since 1994, registered voters in the precincts they inhabited in 1991 so as not to concede any victory to the policies of ``ethnic cleansing'' that fueled much of the war.

On Sunday, hundreds of Croat refugees in west Mostar boarded buses headed east, as their Muslim counterparts headed west. For some, the neighborhoods they returned to were virtually unrecognizable.

Hurija Kukuruzovic, her head covered with a traditional Muslim scarf, clutched her sister-in-law Raha's hand and peered anxiously at the crucifix erected over the Croatian Roman Catholic school where they had come to vote in Buna, a southern suburb.

``We lived in the same house 40 years, we married brothers and they died here,'' she said. ``Now that house is ground to dust, but we want to come back.''

For Vesna Dragoje, a Croat, returning to the hilltop suburb of Gnojnice was without joy.

``Yes, my house is still standing,'' she shrugged, leaning against the wall of the local schoolhouse to seek shade and flapping her identification card to create a breeze in the midday heat. ``Refugees live there.''

She was in no hurry to return, she said, and would vote for the Croatian Democratic Union, which advocated separation in a campaign that touted ethnic ``purity.''

About 50,000 people also fled Mostar in the fighting, and thousands who are now refugees in Europe were bused to polling stations set up in Germany, Sweden, Norway and Switzerland.

``The election will work. It has to work,'' Dzenan Hazirovic said a few minutes after he arrived in Stockholm after a bus ride from Denmark. ``I want to go back.''