Diplomatic tensions soared Sunday between Balkan rivals Serbia and Croatia after Croatia refused to allow a private visit by Serbia's populist president to the site of a World War II concentration camp where tens of thousands of Serbs were killed by pro-Nazi authorities in Croatia.
Croatia's authorities said they learned about the planned visit to the Jasenovac camp by Serbian President Aleksandar Vucic through "unofficial channels." Foreign Minister Gordan Grlic Radman told reporters that the fact that the Croatian government had not been formally notified of the visit was "unacceptable."
"The Ministry of Foreign Affairs would like to stress that in the planning of any visit by foreign officials the time, nature and program of the visit should be subject of official communication and agreement by both sides," said Grlic Radman. "This was not a trip to the seaside. The president of a country is a protected individual."
Croatia's decision sparked outrage in neighboring Serbia, where officials described it as "scandalous." Serbia's hardline Interior Minister Aleksandar Vulin said all Croatian officials from now on would have to announce any transit or visit to Serbia and would be placed under "special regime of control." He did not elaborate.
"This was an anti-European and anti-civilization decision and brutal violation of the freedom of movement," Serbian Prime Minister Ana Brnabic told the pro-government Pink television. "I don't know what our relations will look like in the future ... This is sending a frightening message."
Relations between Serbia and Croatia have remained tense since the breakup of the former Yugoslavia and the 1991-95 war in Croatia that erupted when its Serb minority, backed by Serbia, rebelled against Croatia's independence. More than 10,000 people were killed in the war.
Although the two nations have pledged to work to resolve remaining problems from the conflict — such as finding those still missing — occasional diplomatic spats have marred the postwar efforts. Serbia's populist authorities have insisted that Croatia's government has not done enough to acknowledge its World War II past, while Zagreb accuses Serbia of using the issue for internal politics and refusing to deal with own role in the 1990s' war.
"We see this as a provocation," Grlic Radman said. He added "such a visit is not sincere, it is not about honoring the victims" of the Jasenovac camp, where tens of thousands of Croatia's Serbs, Jews and Roma perished in brutal executions during the WWII rule of the pro-Nazi authorities.
Vucic, a former ultranationalist who supported the Serb rebellion in Croatia in the 1990s, has scheduled a news conference for Monday. He responded Sunday in an Instagram post featuring a photo of the Jasenovac monument.
"You (Croatia) just do your job! The Serbian people will live and never forget!" said Vucic.