WARSAW: The United States and Poland on Saturday appealed for Belarusian President Alexander Lukashenko to engage with civil society, as the strongman leader faces the biggest challenge to his rule since taking power in 1994.

US Secretary of State Mike Pompeo, on a visit to Warsaw, said he had been consulting with European partners since a disputed presidential election in Belarus on August 9.

"The common objective is to support the Belarusian people to achieve their own sovereignty, their own freedom, to build out what you're seeing happen in these protests," he said.

"We urge the leadership of Belarus to broaden the circle... to engage with civil society in a way that reflects the central understandings that the Belarusian people are demanding," Pompeo said at a joint press conference with his Polish counterpart Jacek Czaputowicz.