Cheering crowds set off fireworks in Pristina yesterday after a former Prime Minister of Kosovo was acquitted of the ethnic cleansing and torture of Serbs in a trial plagued by accusations that witnesses were intimidated.

Ramush Haradinaj, 39, a former nightclub bouncer turned guerrilla leader in the Kosovo Liberation Army (KLA), will return to a hero's welcome and a leading political role in the new country, which declared independence from Serbia in February.

The acquittal of the most senior ethnic Albanian to appear before the International Criminal Tribunal for the Former Yugoslavia on charges of crimes against humanity provoked condemnation from Belgrade. It also looks set to exacerbate tensions between ethnic Serbs and Albanians in Kosovo.

Mr Haradinaj, who was briefly Prime Minister in 2004-05, maintained his innocence throughout his trial. Despite the prosecution, some UN officials in Kosovo continued to view him as a strong political leader capable of bringing reconciliation with ethnic Serbs.

In a statement issued in Pristina after the verdict, Mr Haradinaj said that he would dedicate the rest of his life to creating a free and fair society for people of all ethnic backgrounds in Kosovo. “This is a verdict that strengthens Kosovo. We endured a difficult liberation struggle that cost many lives,” he added.

“Today we are a free and sovereign nation. We can now build a dynamic and united society that is based on the rule of law and respect for the fundamental rights of all citizens.”

The judges in The Hague also acquitted another senior KLA figure but sentenced Mr Haradinaj's uncle, Lahi Brahimaj, to six years for the cruel treatment and torture of two unnamed witnesses who were regularly beaten at a KLA-run prison camp.

The trial of Mr Haradinaj, on charges that he led attacks on Serbs and Roma during ethnic fighting in 1998, caused a deep rift in the UN. It was alleged that he had taken part enthusiastically in a joint criminal enterprise with his co-accused of ethnic cleansing during the conflict of 1998-99, including the murder of 30 civilians whose bodies were retrieved from a lake.

The West was divided on Mr Haradinaj and his activities. Carla del Ponte, the war crimes prosecutor who stepped down this year, said she wanted to prove that he had blood on his hands. But Soren Jessen-Petersen, a former UN administrator of Kosovo, praised his “dynamic leadership, strong commitment and vision”.

Mr Haradinaj was allowed to return to Pristina and to continue limited political activity after stepping down as Prime Minister and voluntarily submitting to his indictment in 2005 - concessions not granted to any other prominent suspect at The Hague.

Ms del Ponte claimed that the perception in Kosovo of UN support for the former leader had “a chilling effect on witnesses and deters potential witnesses from speaking to investigators”. Several refused to testify, even under threat of prosecution.

There was outrage in Belgrade at the verdict. Vojislav Kostunica, the Serbian Prime Minister, said: “Today's dark decision by The Hague tribunal shows that the purpose of that court is not justice."

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