Aleksandar Nakjevski

The appeals court said in a statement on Monday that it has upheld the six ethnic Albanians' sentences and rejected their appeal as "ungrounded".

Their defence had demanded acquittal due to a lack of evidence, insisting the case was a political prosecution staged by the government.

The focus of the protest will be the controversial case, called Monster by the authorities, in which six ethnic Albanians were jailed for life for killing five fishermen. Besa [Oath] insists that the trial was a politically motivated set-up by Gruevski.

The covertly-recorded tapes of Macedonian officials' conversations that the opposition says it plans to publish soon could undermine the official story about the six men convicted of the murders at Smilkovci Lake near Skopje in 2012, the head of the opposition Social Democrats, Zoran Zaev, said on Wednesday.

Prosecutor Gordana Geskovska told the Skopje court in her closing arguments on Friday that the murder of five ethnic Macedonians by a group of alleged Albanian extremists during Orthodox Easter in 2012 was an act of terror carried out in order to provoke ethnic strife.