Photo of Toyota Aygo courtesy of Geneva International Motor Show.

Photo of Toyota Aygo courtesy of Geneva International Motor Show.

General Motors, Fiat, Renault, and Toyota introduced subcompact "city cars" at the Geneva International Motor Show that will bring efficient mostly three-cylinder engines to the European market.

General Motors offered several vehicles under its Opel and Vauxhall nameplates that will compete with the Fiat 500, including the Vauxhall Adam, Open Adam Rocks, and Astra VXR sport compact.

The Opel Adam Rocks is a production hatchback powered by a 1.0L Ecotec turbocharged three-cylinder engine generating 114 horsepower. The Adam Rocks will go on sale as early as this summer, reports Motor Trend.

The sportier Adam S variant (a "close-to-production" concept) will be sold as a Vauxhall in the United Kingdom and an Opel everywhere else. The Adam S is powered by a turbocharged 1.4L Ecotec four-cylinder.

Fiat introduced its Panda Cross variant of the Panda in all-wheel drive. It will be offered with either a 1.3L four-cylinder diesel engine or a turbocharged two-cylinder engine with 90 hp. Both engines get stop-start technology and a six-speed manual transmission, reports Autoblog.

The 2014 Renault Twingo, which was developed alongside the new Smart ForFour, is a rear-engine car with a choice of two three-cylinder engines. It will be offered as a five-door hatchback, reports Auto Express.

Toyota introduced its four-door Aygo with a distinctive X pattern on the front of the vehicle. Toyota is offering a choice of two three-cylinder engines and a choice of a five-speed manual or automatic transmission. The vehicle generates 68 horsepower, reports the New York Daily News.