AUGUST sunshine filters through the maple trees that line the wide boulevards of this Bosnian Serb-held city, warming the backs of young couples on Sunday morning strolls and friends sipping coffee at sidewalk cafes.
But amid the idyll, a vicious cycle of "ethnic cleansing" is thriving that Western officials worry may quickly spread to powerful Serbia.
Most of the 150,000 Serbs "ethnically cleansed" from Croatia's Krajina region last week have passed through Banja Luka and are either in Serbia itself or close to the border. Exhausted and bitter, they are eager to blame someone for the loss of their villages that were in Serb hands for centuries.
"Everyone is guilty, everyone betrayed us," says Dario Juric, a Croatian Serb soldier who fled the town of Petrinja with his family.
Who Mr. Juric and the other 150,000 Croatian Serb refugees - the victims of the largest single incident of ethnic cleansing in the former Yugoslavia - blame for their plight is crucial, Western aid officials say.
But with at least 75 percent of the refugees choosing to resettle in Serbia, they could destabilize Serbian politics by blaming President Slobodan Milosevic for not defending them or demand that Serbia's minorities be removed to make room for them.
"Of course they are angry, but the question is where will this anger be directed," says Jacques De Milliano, director of Doctors Without Borders, in the Netherlands. "They can direct it at Milosevic, or maybe he will redirect it at Kosovo [Albanians] or Vojvodina [Croats] or Sarajevo [Muslims]."
The former Yugoslavia's cycle of ethnic cleansing has entered high gear again this month, according to Western officials. The harrowing process of creating three ethnically pure ministates out of multiethnic former Yugoslavia continues grinding on.
Following the Aug. 4 Croatian offensive that led tens of thousands of Serbs to flee here, the Catholic archbishop of Banja Luka announced Friday that over 1,000 Croatian and Muslim families - 5,000 people - had been forced from their homes by angry Serb refugees.
Train to Kosovo
In an unprecedented move that UN officials worry could spark an uprising in Serbia's Kosovo region, the Serbian government is planning to resettle 5,000 refugees in Kosovo, which is 90 percent Muslim Albanian and has been ruled by martial law since 1989. A train with 1,000 Croatian Serb refugees was expected to reach Kosovo yesterday.
In interviews, exhausted and embittered Serb refugees here appear to be in no mood for compromise.
A three- to five-day journey through punishing heat and in monstrous traffic jams has led several thousand refugees to the Kozara army barracks here - a breeding ground for the hatred that drives ethnic cleansing.
As a garbled public address system calls out the names of sons, mothers, and grandparents trying to reunite with families, bitter young men sit on suitcases that contain all their worldly belongings. Elderly couples sleep beneath pine trees to escape the stifling heat. A rancid smell oozes from dozens of trash heaps.
"We were shelled by the Croats. They hid in front of us near Petrovac," says Soka Volarevic, an elderly Serb woman who fled the town of Bankovac with her husband and three grandchildren last week. "Two men, who were civilians, were killed and a few people wounded."
Several Serb refugees said columns of fleeing civilians had been shelled by the Croatian Army.
Dr. De Milliano says the claims are credible and atrocities occurred, but not on the scale of those allegedly committed during the fall of the UN-declared "safe areas" for Muslims of Srebrenica and Zepa.
Western officials worry that the "Banja Luka model" could be quickly carried to neighboring Serbia by the angry refugees. On the streets here, Bosnian Serb soldiers drive French military jeeps stolen from the UN and repainted. One black pickup sports a hood ornament - a fake human skull with a blue UN peacekeeper's helmet strapped to its chin.
The western Bosnia city had a prewar population of 200,000 that included large Croatian and Muslim communities. After a series of ethnic cleansing campaigns that began in 1992, approximately 12,000 Croats and Muslims remain in the area.
Following each Croatian Army seizure of Serb territory in neighboring Croatia, revenge has been taken on Croats here, including the dynamiting of a Roman Catholic church that killed a priest this spring.
Whether the same revenge attacks will begin in Serbia now is unclear. But according to Serb refugees, someone must be held accountable for the greatest Serb defeat since World War II. "We're waiting for a bus to Serbia. We have no idea what we are going to do. We don't have any relatives there," says Jovan Manojovic, who fled Knin with his wife and two sons last week. "It wasn't very beautiful, but it was everything we had."