The United States is sending 26 tons of humanitarian aid to the Balkans to help with relief efforts after floods devastated the region, the Pentagon said Monday.

The assistance included water purification units, water cans, generators, fuel, kitchen equipment, sleeping bags, shovels and wet weather gear, a Pentagon spokesman, Lieutenant Colonel Cathy Wilkinson, said.

Bosnia said Monday it was witnessing "the biggest exodus" since the 1990s war after the worst floods in a century inundated huge swathes of the Balkans, killing at least 47 people.

Muddy waters from the Sava River have submerged houses, churches, mosques and roads in Bosnia, Serbia and Croatia after record rainfall last week wreaked havoc across the region.

In a potentially deadly side-effect to the record-breaking floods that have engulfed Bosnia, officials warned on Monday that unexploded mines left over the 1990s conflict could be dislodged and moved.

"Water and landslides have possibly moved some mines and taken away mine warning signs," said Sasa Obradovic, an official of Bosnia's Mine Action Center.

The heaviest rains in more than a century have sparked floods across Bosnia and Serbia, claiming at least 16 lives and leading to the evacuation of some 15,000, officials said Saturday.

"Six bodies were found in the northern Bosnian town of Doboj after floods started to withdraw from the streets. Unfortunately, this is probably not the final toll," Milorad Dodik, president of Serb-run entity in Bosnia, told reporters.

Severe flooding in Serbia and Bosnia has forced schools to close and hundreds of people to evacuate their homes and left thousands more without power.

In Serbia one person has drowned and a state of emergency has been declared in the worst-hit areas after two days of torrential rain.

The new prime minister of Serbia traveled to Bosnia on Tuesday, pledging to respect borders and rebuild ties that remain tense nearly two decades after the devastating conflict that tore the region apart.

"I arrived for a visit to Sarajevo and Bosnia-Hercegovina as a friend, as someone who represents a country that respects the territorial integrity of Bosnia," Serbian Prime Minister Aleksandar Vucic told reporters after meeting his Bosnian counterpart Vjekoslav Bevanda.

A U.N. war crimes court upheld all charges against Bosnian Serb ex-army chief Ratko Mladic on Tuesday, saying he "has a case to answer", including for his role in Europe's worst massacre since World War II.

Mladic, 72, appeared before judges at the International Criminal Tribunal for the former Yugoslavia (ICTY) half-way through his trial to hear whether they deem that enough evidence exists to continue trying him for his role in Bosnia's bloody 1992-95 war.

The Dutch defense ministry said Thursday it would pay 20,000 euros to relatives of three Bosnian Muslim men murdered after peacekeepers expelled them from a U.N. compound at Srebrenica in 1995.

The announcement follows a Dutch court's landmark ruling last year that the state was liable for the deaths, the first time a government has been held responsible for the actions of peacekeepers operating under a United Nations mandate.

Croatia on Monday said Serbia was "in denial" over genocide allegedly committed in the early 1990s, at the start of a court case that threatens to further sour relations between the Balkan neighbours.

"Many political leaders in Serbia have maintained an attitude of denial" about the alleged genocide, Croatia's representative Vesna Crnic-Grotic told the Hague-based International Court of Justice (ICJ).

Brussels accused Bosnian politicians on Tuesday after negotiations on the Balkan country's bid to join the EU collapsed over the implementation of a key European Court of Human Rights' ruling.

"The result of last night's meeting of the parties' leaders on implementation of the judgment of the European Court of Human Rights in the Sejdic and Finci case was so deeply disappointing," Fuele told reporters in Sarajevo.