FRANKFURT -- The world's carmakers showed off the next generation of cleaner, smaller, and higher-mileage vehicles at the Frankfurt auto show Tuesday, but all the thumping sound systems, slick videos and glossy concept cars could not obscure the anxiety about Europe's financial crisis.

The industry's fortunes have largely turned around since a recession emerged from the 2007-2009 financial crisis.

But many insiders are keeping close watch on the fallout from Europe's debt crisis and worries about the U.S. economy -- and hoping political leaders quickly grasp solutions.

There are concerns that the recent stock market turmoil could dent consumer confidence or that a debt default by Greece could shake the banks business relies on.

Some executives urged a firmer response from Europe. Fiat and Chrysler CEO Sergio Marchionne called on German Chancellor Angela Merkel, who will open the show to the public on Thursday, to step up.

"I think she needs to be part of a permanent solution to this problem," Marchionne said, referring to the leader of the European Union's largest economy. "She needs to force a fundamental change in the system."

Renault and Nissan CEO Carlos Ghosn said he thinks there is "enough common sense and political will to avoid Armageddon ... like in 2008," during the financial crisis. "But it still could happen," he said.

This year's 64th International Motor Show in Frankfurt is nevertheless more cheerful than its 2009 predecessor, which took place during the recession. Organizers said 1,007 exhibitors have signed up -- up from 781 last time.

German car makers like BMW, Daimler, Volkswagen and Porsche have put up strong profits, thanks in part to sales in fast-growing, emerging markets that for now have made up for weaker growth at home in Europe.

The confidence of the home carmakers showed clearly in a lavish display of Daimler's Mercedes-Benz and Smart lines against the background of a video screen several stories high and a deafening sound system.

CEO Dieter Zetsche said that no matter the "turbulence on the Frankfurt stock exchange" in recent days, "all lights are green" at the company.