A NEW conflict is brewing between nationalist Croatian forces and their former allies, the Muslim-led Bosnian Army. The breach could deal a fatal blow to the fragile international peace effort for Bosnia-Herzegovina.
"We will be ready to fight. They will be too. If they do, it will be a big mistake," warns Humo Esad, the Bosnian Army second-in-command in Mostar, the war-torn country's second-largest city.
The crisis has erupted less than two weeks after Bosnia's Muslim president, Alija Izetbegovic, joined Bosnian Croat leader Mate Boban in signing the final parts of the plan authored by Cyrus Vance of the United Nations and Lord David Owen of the European Community.
Tensions have been building since the Croatian Defense Council told the Bosnian Army that they have until April 15 to withdraw from areas included in the three Croat-dominated provinces that would be created by the plan.
The Croatian militia, known by its initials HVO, is the military wing of Mr. Boban's chapter of the nationalist Croatian Democratic Union, led by President Franjo Tudjman of neighboring Croatia.
If the demand, which Croat leaders say is only an attempt to implement the Vance-Owen demilitarization plan, is not met, the HVO said it would "unilaterally impose its authority" on the proposed Croat regions.
The Croat ultimatum threatens to unhinge an accord brokered by Mr. Vance and Lord Owen in January that ended weeks of fierce fighting between the Bosnian Army and the HVO. Those clashes were ignited when Boban ordered all Bosnian troops in Croat-controlled areas to submit to HVO command. The HVO, armed by Croatia, overran large areas of central Bosnia before the truce and expelled Muslim civilians in "ethnic cleansing" operations.
In addition, the ultimatum strengthened a belief widely held among Bosnian officials and Western diplomats that Boban and his patron, President Tudjman, seek ultimately to partition Bosnia by capturing Croat-dominated areas and merging them with Croatia.
That view was first prompted by Boban's declaration last summer of an autonomous "Croatian community Herceg-Bosna" in Croat-dominated western Herzegovina, which borders Croatia's Dalmatian coast and includes central areas of Bosnia.
"The Serbs are kicking down the front door, and the Croats are sneaking in the back," claims a Bosnian soldier in Mostar's centuries-old Muslim quarter.
But Jadranko Prlic, the self-styled acting prime minister of "Herceg-Bosna," says the ultimatum reflects only HVO's intention to implement the demilitarization clause of the Vance-Owen plan. "We signed the document and the Muslims signed the document, and it is one of the real ways to overcome problems between Muslims and Croats," he says.
Mr. Prlic concedes, nonetheless, that the HVO ultimatum could lead to bloodshed. "We expect everything. We don't want this struggle. We don't have any reason for this struggle," he says.
Nowhere has the ultimatum raised greater concern of serious violence than in Mostar, nestled on the southern fringe of Bosnia. To comply with the HVO demand, the Bosnian troops in Mostar would have to abandon their homes, something they clearly find unacceptable.
"In a few days there will be a war between the HVO and the Bosnian Army," worries Ivice Antic, a Croatian electrician who has lived in Mostar his entire life.
The picturesque city, which sits astride the Neretva River, had a pre-war population of about 85,000: about 41 percent Muslim, 39 percent Croat, and 20 percent Serb. Last June, the HVO and the Bosnian Army together drove Bosnian Serbs out of Mostar after several months of indiscriminate Serbian bombardments.
The HVO has since seized virtual control of Mostar, bringing in soldiers from both its base in western Herzegovina and from Croatia and making the city economically dependent on the neighboring state.
Mostar's telephone links run through Croatia, which also supplies most of its food and newspapers. Electricity comes from five HVO-controlled hydroelectric dams on the Neretva that also provide power to Croatia.
The HVO presence has stoked indignation among Bosnian Army commanders who accuse the better-armed Croats of deliberately ensuring that Bosnian troops remain weaker. Mr. Esad, the Bosnian officer, says the HVO regularly seizes as "taxes" portions of Bosnian government arms shipments that can only reach Mostar by breaking the UN embargo through Croatia and HVO-controlled western Herzegovina. "They say we are together when they need us. When they don't need us, they play their games," Esad remarks bitterly about the Croats.