Spyware from an Israeli company was used to target the phone of the rector of the Belgrade university who has played a prominent role in nearly two years of protests against Serbia 's populist leader Aleksandar Vucic, a digital rights group said on Monday.

The Balkan country is holding a tense election this weekend that is seen as a showdown between the protesting student movement and Vucic, who is seeking to extend his right-wing Serbian Progressive Party's 14-year rule.

In September, digital rights groups reported that at least 14 activists and students had their phones hacked and infected with spyware, including NSO Group's Pegasus.