“Plavsic was transported this morning to Arlanda (airport),” Swedish Prison and Probation Service director Lars Nylen said in a statement, adding that she boarded the plane and left the country.

Plavsic, 79, landed shortly after 2pm at Belgrade airport and immediately left for her apartment in the Serbian capital, accompanied by Bosnian Serb Prime Minister Milorad Dodik.

Upon arriving at her home, Plavsic, who also has Serbian citizenship, briefly said she would spend some time with her brother and sister-in-law, B92 television reported.

“I am happy to be free after nine years,” she said, adding that she would “soon” talk to the press.

Plavsic was sentenced in February 2003 to 11 years behind bars after she admitted playing a leading role in a campaign of persecution against Croats and Muslims during Bosnia’s 1992-95 war.

She is the highest ranking official of the former Yugoslavia to have acknowledged responsibility for atrocities committed in the Balkan wars of the 1990s.

She served her sentence at a women’s prison in Sweden, where the government last week confirmed she would become eligible for release on Tuesday after serving two-thirds of her term, in accordance with Swedish law.

The release caused an immediate backlash in neighbouring Bosnia. The Croat chairman of the country’s tripartite presidency Zeljko Komsic cancelled a November 4-8 official visit to Sweden in protest.

“The Swedish government released Plavsic because it wanted to and not because it had to,” Komsic said in a statement released in Sarajevo.

The decision is “particularly unacceptable and embarrassing” as Foreign Minister Carl Bildt had acted as a witness for Plavsic’s defence, visited her in prison and took part in the decision on her release, he said.

Around 30 prisoners sewed their lips together in a protest at Bosnia’s top security jail in the central town of Zenica.

The prisoners, jailed for various criminal offences, were protesting Plavsic’s early release while they were “deprived of that right for a number of years already,” the prison said on its website.

Plavsic surrendered to the UN war crimes tribunal in January 2001 after it had issued an indictment for genocide, extermination, murder, persecution, deportation and inhumane acts.

She struck a plea agreement with prosecutors in October 2002 in which she “admitted to supporting and contributing to achieving the objective of the permanent removal of ethnic populations by force.”

She had expressed remorse and a behavioural report showed she had “exhibited good behaviour” in prison, the war crimes court said. “She has participated in the institution’s walks and she also occupies herself by cooking and baking.”

“Biljana Plavsic was happy about being released and that was all she cared about at that moment. She thanked the prison personnel and boarded the plane. What happens after this is up to her to say,” Nylen said.

Known as the “Iron Lady” for her ruthless leadership, the former ally of wartime Bosnian Serb leader Radovan Karadzic was a fiery nationalist who during the war publicly supported the campaign of persecutions of non-Serbs.

But the former biology professor underwent an extraordinary pragmatic conversion in 1996, which saw her cooperate with the international community, turning the tables on her mentor Karadzic — now on trial for genocide — who was forced to resign.

It was this post-war conduct together with her surprise guilty plea to the tribunal that the judges considered to be seriously mitigating circumstances.

Her release came on the second day of Karadzic’s genocide trial in The Hague which the 64-year-old has so far boycotted, demanding more time to prepare his defence.