KYIV (Reuters) - Thousands of people took to the streets of Minsk and other Belarusian cities on Friday, after a 31-year-old anti-government protester died in hospital following what demonstrators said was a severe beating by security forces.Witnesses said Roman Bondarenko was detained after scuffling with people in plain clothes who had come to a playground to remove red-and-white ribbons representing a months-long protest movement against President Alexander Lukashenko. The interior ministry denied responsibility for Bondarenko’s death, saying he had been killed in a scuffle with civilians. The state Investigative Committee alleged Bondarenko had been drunk. Local media reports contradicted this, citing the official medical report into his death that they said showed he had no alcohol in his bloodstream. The death on Thursday was the latest flashpoint in months of mass protests against Lukashenko following a disputed presidential election in August. The opposition says Lukashenko rigged the vote to secure a sixth successive term. Lukashenko denies electoral fraud and, buoyed by support from traditional ally Russia, has rejected opposition calls to resign or hold new elections.