Magyar made the accusations during a rally in Budapest.
Polls indicate Tisza is leading over Fidesz.
The allegations come ahead of Hungary's elections on April 6.
Strategic angle: Opposition leader Péter Magyar labels Viktor Orbán a traitor, alleging Russian interference in upcoming elections.
Magyar made the accusations during a rally in Budapest.
Polls indicate Tisza is leading over Fidesz.
The allegations come ahead of Hungary's elections on April 6.