European diplomats say Cypriot officials are threatening to veto sanctions against Minsk if the EU does not consider action over a separate dispute in the Mediterranean Sea.
European diplomats have told Euronews that EU sanctions on Belarus are being held up by Cyprus with only a few days left until a key meeting of European foreign ministers on Monday.
The island nation, one of the EU's smallest members, has threatened to block measures against Belarusian President Alexander Lukashenko's government because of a separate row involving Turkey.
On Friday, France appeared to support Cyprus' demand that the bloc must also consider sanctions over Turkish oil and gas exploration in the eastern Mediterranean.
European leaders vowed nearly a month ago that they would act upon a list of Belarusian officials connected to fraud and police violence following the disputed presidential election.
But the EU can only impose sanctions on human rights issues if all 27 members of the bloc support them.
European Commission President Ursula von der Leyen this week said the bloc should drop its unanimity rules on the issues of human rights and sanctions implementation so that decisions can be made more quickly.
Belarusian opposition candidate Sviatlana Tsikhanouskaya said activists were working to identify police and soldiers allegedly involved in street violence in Belarus.
Turkey is embroiled in a separate dispute with Cyprus and Greece over maritime borders and gas exploration rights in the eastern Mediterranean.
One senior source who attended a Brussels meeting on Thursday with Josep Borell, the EU’s foreign policy chief, told Euronews: “The situation with Cyprus is extremely difficult, and there is no sign Cyprus will retreat on threatening to block sanctions against Belarus unless the EU announces sanctions against Turkey.”
Clement Beaune, the French minister for European Affairs, said after talks with Cypriot Foreign Minister Nikos Christodoulides on Friday that the EU must be ready "certainly to resort to sanctions [on Turkey] if developments don't proceed in a positive direction."
French President Emmanuel Macron has supported Cyprus and Greece in the dispute and last month deployed fighter jets and a frigate warship to the region.
Turkey says the question of maritime borders in the eastern Mediterranean is unresolved and that it is entitled to explore for oil and gas there.
However, both sides have indicated they are open to talks and this week, Turkey said it was temporarily withdrawing a naval exploration vessel to port for maintenance.