Geneva - Top automakers are vowing not to give up on weak-selling electric vehicles - even as they unveil an array of powerful luxury cars with conventional engines aimed at a growing global market.

BMW AG CEO Norbert Reithofer said Tuesday at the Geneva International Motor Show that his company cannot do without battery-powered vehicles such as its i3 urban compact.

"In the future, electric drive vehicles will be in demand," he said, adding that the Munich-based automaker could not meet its targets to reduce emissions without them.

Only about 75,000 of the 12.5 million vehicles sold last year in Europe were electrics or hybrids. Still, auto companies have sunk billions into developing alternative propulsion vehicles over the long term due to government requirements to limit vehicle emissions and with an eye to restrictions on autos in China due to heavy air pollution. The European Union requires companies to average 95 grams of CO2 per kilometer (0.6 miles) for their new cars by 2021, down from a limit of 130 grams per kilometer this year.

Daimler CEO Dieter Zetsche said hybrids combining internal combustion and batteries were "truly attractive cars that represent the best of both worlds" and serve as a bridge to future no-emissions vehicles. Daimler introduced a rechargeable plug-in hybrid of its C-class sedan at the show.

Zetsche cautioned, however, that the long-life batteries needed for electrics to conquer the market are at least five years off.

The calls to keep developing alternative-drive cars come even as high-end luxury cars take pride of place at this year's Geneva show. Lamborghini, Ferrari, Audi and McLaren all are unveiling high-speed machines costing hundreds of thousands, while Daimler has the Maybach Pullman stretch limousine, which will go on sale for north of $561,000.

Volkswagen CEO Martin Winterkorn stressed his company's commitment to new technologies even as the company's Lamborghini brand showed off its Aventador LP 750-4 Superveloce, a sleek beast of a sports car with an enormous 750 horsepower and a top speed of more than 217 mph. It puts out 375 grams per kilometer of CO2.

Volkswagen also unveiled a concept sport coupe that's hybrid-driven and can reach 150 mph. It emits only 46 grams of CO2 per kilometer.

Auto executives were cautiously optimistic for sales this year in China, the United States and Europe - the three sales pillars for export-oriented German carmakers.