President Vladimir Putin accused his US counterpart Barack Obama of a hostile approach towards Russia, warning in a Cold War-style tirade that Moscow would not be blackmailed by the West over Ukraine.

Putin fired off his combative comments shortly before he arrived amid tight security to a red carpet welcome in Belgrade, seeking to cement Russia's influence in its loyal European ally.

The European Union told Belgrade on Tuesday it should prove its credentials as a future member during an upcoming visit by Russian President Vladimir Putin to Serbia, a historic Moscow ally.

The EU has declared Putin persona non grata for his role in the Ukraine crisis but he can still count on a warm welcome Thursday in Belgrade, which has refused to emulate the tough sanctions imposed on Russia by Brussels.

Serbia's prosecutor for organized crime said Wednesday he has charged five men for terrorism over recruiting, financing and transporting fighters for conflict in Syria.

The five are accused of "joining forces to finance terrorism, train and recruit people for terrorist acts," the prosecutor Miljko Radisavljevic said in a statement received by Agence France-Presse.

With the world on high alert over foreign fighters joining jihadist ranks in Syria and Iraq, Balkan states are launching efforts to clamp down on recruiting in their region, considered fertile ground by Islamists.

Of the more than 20 million people in southeast Europe, more than five million are Muslims, and an economic slump in weak states battered by past wars has fired up some of the disenfranchised.

A top Kosovo Serb politician pleaded not guilty to charges of war crimes against ethnic Albanians in 1999 and 2000 at the start of his trial here Tuesday.

"I am absolutely not guilty," Oliver Ivanovic told an EU tribunal in the northern town of Kosovska Mitrovica.

One person was killed and another was missing after heavy rains brought a new wave of flooding to Serbia and Bosnia this week, just three months after historic floods killed almost 80 people.

Torrential rain in the western Serbian town of Banja Koviljaca led to a 65-year old man drowning after his house was flooded, Beta news agency reported, quoting local police.

A Bosnian Serb who ran illegal camps where prisoners were tortured and killed during Bosnia's 1992-1995 war has been sent to prison for 15 years for "crimes against humanity", officials said Friday.

Bosnia's war crimes court found Branko Vlaco, 61, guilty of setting up and running four "detention centers" in the Sarajevo suburb of Vogosca from May to October 1992, where Muslim and Croat civilians were illegally held.

Serbian President Tomislav Nikolic was booed during a visit to Kosovo on Saturday by ethnic Serbs who accused his government of betrayal for agreeing to normalize relations with the breakaway state.

Nikolic was addressing around 1,000 Kosovo Serbs at a ceremony marking the anniversary of an historic 14th century battle at Gazimestan, around five kilometers (three miles) southwest of the capital Pristina.

Kosovo police fired tear gas on Sunday to disperse stone-throwing protesters who set alight police cars demanding the removal of a barricade on a bridge linking ethnic Albanians and Serbs in the divided town of Mitrovica.

Six policemen and two photographers were slightly injured as about 1,000 ethnic Albanian protesters pelted the police cordon with stones, police said in a statement.

Kosovo's prime minister called on Thursday for the removal of a blockade of flower pots on a bridge linking ethnic Albanians and Serbs in the flashpoint town of Mitrovica.

The pots were placed across the bridge by Serbs from the northern part of the divided town a day earlier, replacing an already existing barricade of earth and concrete.