(Adds background, details on new forecast)
MOSCOW, July 8 Russian car sales plunged 17.3 percent year-on-year in June, according to a lobby group for Europe's top carmakers, accelerating their recent slide and leading the group to slash its forecast for sales in the country this year.
The Association of European Businesses (AEB) said on Tuesday it now expected sales of cars and light commercial vehicles in Russia to drop 12 percent this year to 2.45 million units - far more pessimistic than its forecast earlier this year for a 1.6 percent decline.
Auto sales have tumbled in Russia as a weakening economy has been further hit by Western sanctions over Ukraine, and as people delay making large purchases.
A decline this year would follow a 5.5 percent fall in car sales in 2013, which brought three years of double-digit percentage growth to an abrupt end.
"The market continues its downward trend, at an accelerating pace," said Joerg Schreiber, chairman of the AEB Automobile Manufacturers Committee (AMC). "In the opinion of AMC member companies, the market weakness has not reached its bottom yet."
Western automakers such as General Motors, Ford and Renault have invested heavily in Russia on the expectation it would soon become Europe's biggest car market. (Reporting by Megan Davies; Editing by Mark Potter)