KYIV (Reuters) - The chief editor of one of Belarus' leading independent news organisations has gone missing after police searched her home overnight, the country's reporters' association said on Wednesday, as authorities pursue a crackdown on dissent.

       Online news agency BelaPAN had been unable to contact either Irina Levshyna or one of its reporters, Zakhar Shcherbakov, the association said. Shcherbakov's home and that of a third BelaPAN reporter were also searched, it said.

       Belarus security officials were unavailable for comment and Reuters could not immediately speak to BelaPAN.

       Authorities have waged a campaign of repression against non-state media, human right groups and leaders of protests against the regime of President Alexander Lukashenko since last August, when he was re-elected in a ballot that the opposition and western observers say was rigged.

       The journalists association has said at least 30 Belarusian journalists are in jail and that police are conducting about 50 separate criminal investigations against members of the media.

       Security forces have stepped up their crackdown in recent weeks, with police carrying out a series of raids in July against activists, journalists and NGOs, accusing them of organising riots and protests.

       This month, Belarusian sprinter Krystsina Tsimanouskaya was forced to defect while competing at the Olympic Games following a dispute with her coaches in which she said an order came from "high up" to send her home from Tokyo, prompting a barrage of new Western sanctions.

       (Writing by Pavel Polityuk; editing by John Stonestreet)