By Andreas Cremer and Valerie Volcovici BERLIN/WASHINGTON - Volkswagen shares plunged by nearly 20 percent on Monday after the German carmaker admitted it had rigged emissions tests of diesel-powered vehicles in the United States, and U.S. authorities said they would widen their probe to other automakers. German officials, alarmed at the potential damage the scandal could inflict on its car industry, urged Volkswagen to fully clear up the matter and said it would investigate whether emissions data had also been falsified in Europe. The U.S. Environmental Protection Agency (EPA) said on Friday the world's biggest carmaker by sales used software for diesel VW and Audi branded cars that deceived regulators measuring toxic emissions and could face penalties of up to $18 billion.

Volkswagen shares plunge on emissions scandal, U.S. widens probe