It was the worst violence in the war-torn Balkan state, patrolled by 20,000 peacekeeping troops, in years.
Twenty-one peacekeepers Americans among them were slightly injured in the melee in the southwestern city of Mostar, NATO spokesman Lt. Lars Anderson said. The others injured were from Italy, France, Spain and Morocco, he said.
Four Bosnian civilians also were injured, Mostar Radio said. In Rome, officials said 11 of the injured peacekeepers were Italian paramilitary police.
The trouble started when armed, masked U.N. and Bosnian police backed by NATO troops seized the Mostar headquarters of the bank Hercegovacka Banka and 10 branches throughout Bosnia-Herzegovina.
The hard-line Croatian Democratic Union is believed to use the bank to promote its campaign to establish a separate, Croat-run ministate, said Ralph Johnson, deputy to chief international administrator Wolfgang Petritsch.
"I want to make clear that the international community's campaign to make sure that those who fund illegal structures are dealt with will continue," Johnson said.
The raid triggered daylong rioting in Mostar, 45 miles southwest of Sarajevo and a stronghold of the Croatian Democratic Union, known by its Croatian initials, HDZ.
During the takeover, mobs swarmed the bank's headquarters, beat police and international officials, destroyed records and looted the building. Johnson said. Crowds attacked NATO vehicles, overturning several and setting one on fire. Gunshots rang out in the streets.
International peace officials trapped by a mob in the Ero Hotel where their offices are were also rescued, whisked from the building in Spanish armored personnel carriers. Shots had earlier been fired in the area. It was not clear if any other officials remained trapped elsewhere.
BBC reported that some peacekeepers and officials were taken hostage.
NATO closed the main bridge across the Neretva River dividing the city into Muslim and Croat districts and called in reinforcements from throughout the country.
The HDZ called the raid "armed robbery," and the president of the bank's board of directors, Ante Ljubic, refused to accept the authority of the newly appointed manager, Tobi Robinson.
"We also request that Robinson and her armed escort immediately leave the units of Hercegovacka Banka and allow the legal administration to enter the bank," Ljubic said in a statement.
In Zagreb, Croatia, Bosnian Foreign Minister Zlatko Lagumdzija backed the raid Friday, saying the bank'management had long been "dubious."
The takeover could prevent "a dream of all extremists from coming true: that the national banks would be in one nation's hands and the national money in the pockets of national thugs," he said during a one-day visit to the Croatian capital.
Tensions have been rising steadily in Croat areas after the HDZ declared last month that it would break off its alliance with the country's Muslims and set up a Croat government. Under the 1995 Dayton peace agreement that ended the Bosnian war, the country was divided into a Serb-run ministate and a Muslim-Croat Federation.
After the war, the HDZ maintained parallel government institutions in southwestern Bosnia over the objections of international administrators. However, many Croats, the smallest of the three ethnic groups here, felt they had been shortchanged in the division of power.
Petritsch fired the Croat president, Ante Jelavic, and other Croat officials last month over the secessionist threat. International officials suspected the HDZ of planning to finance its ministate with proceeds from the Hercegovacka Banka.
As part of its campaign, the HDZ has been calling on Croats soldiers to desert the Bosnian army, and hundreds have complied. Croat war veterans also have been pressuring the remaining Croats to heed the party's call.
On Friday, U.S. peacekeepers bolstered their patrols in the northern Bosnian town of Orasje, where war veterans were trying to convince Croat soldiers to desert. U.S. helicopters hovered over the town and armored personnel carriers roamed the streets while mediators urged the veterans to go home.
Meanwhile, German troops sent reinforcements to the largely Croat town of Kiseljak to prevent militants from taking over a garrison there.
Hercegovacka Banka was founded in 1997 by several private companies and the Franciscan Order, which controls the religious shrine in Medjugorje, a major source of income from pilgrims and donations by Croats living abroad.
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