Austria’s leader called for early elections Saturday after a secretly-recorded video showed his nationalist deputy offering public contracts to a woman he believed to be a Russian oligarch.

Chancellor Sebastian Kurz said he would dissolve the government after the leader of his junior coalition partner, a prominent anti-immigration advocate with links to Russian President Vladimir Putin, resigned. Mr. Kurz’s decision to drop his partnership with the Freedom Party deals a blow to the continent’s far-right movement ahead of European...