The rebel leader in charge of Ukraine’s largest separatist region has won a crushing victory in a controversial election, according to the insurgents’ own exit polls.

European Union and United nations officials condemned the separatist-run elections, saying the vote would “seriously undermine a peace plan for the region.

Alexander Zakharchenko, prime minister of the self-declared Donetsk People’s Republic, was on course to claim 81.37 per cent of the vote in the presidential poll, rebel election chief Roman Lyagin said on Sunday.

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His party was also set to claim 65 per cent of the parliamentary vote.