Anti-corruption campaigner Zuzana Caputova was sworn in as Slovakia's first female president on Saturday, vowing to fight impunity and champion justice in a country shaken by a journalist's murder last year.

The killing of Jan Kuciak, who investigated high-level graft cases, and his fiancee at their home last February sparked mass street protests and hit the approval ratings of the governing leftist party Smer.

Smer is still the most popular party but Caputova's victory in the March presidential vote boosted the opposition liberal alliance Progressive Slovakia/Together, which backed her and aims to unseat the ruling party in a 2020 general election.