Tesla Inc. sales kept sliding across Europe’s biggest electric-car markets in April, despite the company rolling out an updated version of its most popular vehicle.

Tesla’s sales continue to plunge across Europe, even as car buyers there increasingly turn to electric vehicles.

Tesla sales plunged by more than half last month in several European countries in a sign that Elon Musk could struggle to revive the company after he shifts from his Washington cost-cutting work to day-to-day operations again.