The Congress Friday hit out at BJP's prime ministerial candidate Narendra Modi over his caste issue and said that another lie of his had been "exposed"."One more lie of Modi is exposed that he is an OBC by birth. It is evident that with fabricated lies he is trying to fool one and all," senior Congress leader Shakeel Ahmad tweeted.His comment came after a statement issued by Gujarat Congress Thursday said the Gujarat chief minister belonged to an upper caste but called himself an OBC (Other Backward Classes) to garner sympathy.In response, senior Bharatiya Janata Party leader Arun Jaitley had said that since Congress cannot "digest defeat at the hands of a commoner", they have made Modi's "humble origin" an issue."Narendra Modi has never made caste as his identity and his appeal cuts across castes and communities. The ruling dynasty of the Congress cannot digest defeat at the hands of a commoner," Jaitley wrote in his blog."Therefore, they made his humble origin as a tea vendor into an issue. The move backfired," he added.