US Secretary of State Mike Pompeo said Thursday that Washington hoped to work with the EU to resolve the crisis in Belarus where veteran leader Alexander Lukashenko's controversial re-election has sparked unprecedented protests.

Thousands have been arrested following mass peaceful protests that have been brutally quashed by police following Sunday's vote, which opponents say was rigged.

"I'm confident that the EU and the United States share the same concerns about what has taken place and what is taking place in Belarus, and I'm very hopeful that we can collectively work" to address the crisis, he told reporters during a visit to Slovenia.

On Wednesday, Pompeo said Belarusians should be given "the freedoms that they are demanding" and urged authorities in the former Soviet republic not to harm protesters.

Flanking Pompeo in a joint press conference, Slovenian Prime Minister Janek Jansa called for fresh polls in Belarus.

"The only peaceful solution for the current crisis in Belarus is to repeat the elections under the strong presence of the international observation missions," the EU member's leader said.

The Organisation for Security and Cooperation in Europe (OSCE), which has sent observers to Belarus since 2001, was not invited to monitor Sunday's polls.

European Union foreign ministers are set to discuss Belarus at an extraordinary meeting on Friday, with some in the bloc calling for the re-imposition of sanctions.

Hungarian Foreign Minister Peter Szijjarto said Thursday on Facebook that he had spoken to his counterpart Edgars Rinkevics of Latvia, which borders Belarus. 

"We are interested in seeing EU decisions taken that are based on dialogue, that don't preclude future relation building between Belarus and the European Union, and that don't hinder the Eastern Partnership programme either," he said.That programme is a joint initiative between the EU, its members and six Eastern European countries, including Belarus.

Police in Belarus said Thursday they had detained hundreds more protesters as demonstrations continued.

Dozens have been wounded and two people have died as police have used stun grenades, tear gas, water cannon and, in at least one case, live fire to disperse protesters.