HANOVER, Germany, Sept 25 (Reuters) - Volkswagen (VOWG_p.DE) flatly rejected union demands after the first round of bitterly contested talks ended without agreement on Wednesday, as workers at Europe's largest automaker threatened strikes against layoffs and possible plant closures.

Unions on Wednesday criticised Volkswagen for failing to make specific proposals in the first round of talks over the German auto giant's drastic cost-cutting plan, as thousands of workers picketed

Powerful trade unions and executives at Volkswagen will kick off talks over pay on Wednesday that are likely to determine how aggressively Europe's biggest automaker pursues layoffs and potential factory closures in Germany.

German automaker Volkswagen rejected trade union demands for pay increases for German workers and continued to warn of deep cuts instead during initial collective bargaining talks on Wednesday. VW earlier this month cancelled a long-standing job security deal with workers and warned that it could no longer rule out mass layoffs or plant closures as part of an austerity plan at the auto brand.

German auto giant Volkswagen has rejected union demands for pay increases and instead threatened cost cuts during initial collective bargaining negotiations with labour leaders on Wednesday. Labour leaders said VW bosses also refused to provide more details about possible mass layoffs and plant closures that have been threatened by VW management