By Fatos Bytyci and Aleksandar Vasovic
PRISTINA/BELGRADE, June 28 (Reuters) - More than 50 people were injured in clashes on Thursday when the authorities in Kosovo deported a group of visiting Serbs who accused the police of shooting at them, leaving one with life-threatening gunshot injuries.
The group of about 70 mostly young Serbs was travelling in two buses to Gazimestan, a religious and historic site close to the capital Pristina, when police turned them back, arguing they had become "very aggressive, drunk and were provoking both police and citizens".
Kosovo declared independence from Serbia in 2008, but tensions between the 90 percent Albanian majority and the small Serb minority that refuses to accept it is an independent country have persisted, and relations with Belgrade itself have remained strained.
Serbian health authorities said one Serb sustained life-threatening injuries in the clashes and that five others were hospitalised with gunshot wounds. A total of twenty Serbs sought medical care in the towns of Kursumlija and Prokuplje, just outside Kosovo.
Police in Kosovo declined to confirm whether they had fired live rounds at the Serb group.
In Pristina, Kosovo President Atifete Jahjaga said the authorities would stop all such groups in future "as they are seriously violating law and order and further exacerbating the security situation in Kosovo".
Kosovo's Interior Minister Bajram Rexhepi said the Serb youths had thrown stones and other heavy objects at the police shortly after being expelled from Kosovo territory.
Nine Kosovo police officers were treated in hospital and a further 23 policemen suffered minor injuries, he added.
Gazimestan is a field just outside Pristina, where Serbs mark St. Vitus Day and the 1389 Battle of Kosovo, when an Orthodox Christian Serb force led by Tsar Lazar lost a decisive battle to invading Muslim Ottoman Turks.
Ivica Dacic, Serbia's prime minister-designate, said the incident was damaging for peace and stability in Kosovo.
"International troops there have an obligation to preserve peace and security ... All future talks (with Kosovo) must be based on the preservation of security," Dacic told reporters in Belgrade.
In Gazimestan, where the ceremony took place, police searched buses and seized nationalist paraphernalia from visiting Serbs.
Gazimestan is also the place where on June 28 1989 late Serbian strongman Slobodan Milosevic addressed hundreds of thousands of Serbs in a speech that heralded the bloody collapse of communist six-republic Yugoslavia in the 1990s.
Violence between Albanians, Serbs and international peacekeepers flared last year, after Pristina attempted to establish its authority in the northern, predominantly Serb part of the country which still pledges allegiance to Belgrade.
Independent Kosovo has been recognised by more than 90 countries, including the United States and 22 of the European Union's 27 member states. However, Russia and China as well as Serbia itself have refused to recognise it. (Additional reporting by Branislav Krstic in Mitrovica; Editing by Zoran Radosavljevic and Andrew Osborn)