MADRID: The European Union's top diplomat Josep Borell warned Sunday that Belarus should not be allowed to become a "second Ukraine" and said it was necessary to deal with President Alexander Lukashenko.

Brussels rejects the August 9 presidential vote in Belarus that sparked mass protests against Moscow-backed 26-year incumbent Lukashenko's claimed landslide win.

But in Ukraine "tensions between Europe and Russia were settled with shooting, with violence and the disintegration of Ukraine's territory that has lasted to this day," Borell told newspaper the Sunday edition of El Pais.

"The Belarusians' problem today isn't to choose between Russia and Europe, it's to obtain liberty and democracy," he added.

"Europe has no intention of turning Belarus into a second Ukraine."

Tensions between European capitals and Moscow have simmered ever since Russia annexed Crimea in 2014, prompting the EU to impose sanctions that remain in place today.

Borell said the EU must continue dialogue with Lukashenko, comparing his situation to Venezuelan leader Nicolas Maduro, who has also repressed a vocal opposition movement.

"Maduro and Lukashenko are in exactly the same situation. We don't recognise their elections as legitimate," Borell said.

"Nevertheless, whether we like it or not they control the government and we have to continue dealing with them, although we don't recognise their democratic legitimacy."

The Belarusian opposition has called for a further large demonstration Sunday to keep up pressure on the president, who has put the army on alert and warned of foreign meddling in the country.

Several demonstrations following the contested election were violently put down by police, and at least three people have died in the violence.

Dozens have been injured and more than 6,700 arrested, with many detainees reporting they suffered beatings and torture while they were held.