Croatian football strongman and former Dinamo Zagreb chief Zdravko Mamic was sentenced on Wednesday to six-and-a-half years in prison over multi-million-euro abuse of power and graft.

Two international stars -- Real Madrid midfielder Luka Modric and defender Dejan Lovren -- appeared as witnesses during the trial in Osijek providing details of their transfers from Dinamo.

The players' evidence came under official scrutiny.

Croatia captain Modric was charged in March for alleged false testimony over the details of his 2008 transfer from Dinamo to Tottenham Hotspur.

Lovren, questioned over his 2010 transfer from Dinamo to French side Lyon, was also investigated.

Mamic, 58, was not present at the tribunal in the eastern town of Osijek for sentencing. He travelled to neighbouring Bosnia on Tuesday claiming he was not on the run but wanted to avoid "frustration" at the court and "find peace".

But after the verdict was handed down Mamic said he would not return to Croatia until it becomes final.

"I will stay here ... and fight from here. I don't trust Croatian institutions," he told a press conference in Medjugorje, a southern Bosnian town famed for alleged apparitions of the Virgin Mary.

"I wouldn't like to be in the skin of people who 'packed me' all this," he said, threatening a "response .... unseen in this territory".

Mamic is considered the most powerful figure in Croatian football and his trial, that opened in April 2017, was a further problem for a sport already struggling with hooliganism and poor infrastructure.

He was tried along with three others -- his brother and former Dinamo Zagreb coach Zoran Mamic, former club director Damir Vrbanovic, and a tax inspector.

According to the indictment, the corruption cost Dinamo more than 15 million euros ($18 million) and the state 1.5 million euros as cash was embezzled through fictitious deals related to player transfers.

Judge Darko Kruslin found all four defendants, none of whom was present on Wednesday, guilty.

"Zdravko Mamic is sentenced to a total prison sentence of six years and six months," Kruslin said.

The verdict is not final, but, under Croatian law a person sentenced to more than five years in jail must go to prison immediately.

Vrbanovic, also a top Croatian Football Federation official, and Zoran Mamic were sentenced to three years and four years and 11 months in jail respectively.

The tax inspector was jailed for four years and two months.

All four defendants pleaded not guilty.

The trial was held in Osijek because Mamic allegedly has close ties with some judges in Zagreb.

Mamic's connections extend into many spheres of Croatia's public life.

Meanwhile, champions Dinamo voiced "shock and outrage" over the verdict and voiced their firm belief in the defendants' innocence.

Bosnia cannot extradite Mamic as he is its national.

But, Bosnian Security Minister Dragan Mektic explained that if Zagreb demands Mamic could serve his term in the Balkan country.

In the past Mamic repeatedly argued that the probes against him were politically motivated.

Most Croatian football fans see him as the real boss of the football federation and believe its formal chief Davor Suker is merely Mamic's puppet.