(Eds: Updating with Congress reaction)

New Delhi, Sep 8 (PTI) Senior Congress leader Digvijaya Singh today stoked a major controversy by posting a tweet that used abusive language against Prime Minister Narendra Modi, prompting the BJP to demand an apology from his party for the "filthy abuse".

Singh later disowned it, saying retweets are not endorsements, but the trolls did not spare him.

"Retweets are never endorsements. This is the basic principle of Twitter," he said after the controversy erupted.

"I have said it is not mine. I have disowned it. I have not used those words," he clarified, adding that "my tweet does not endorse this."

He added that "my words are that he is the best in the art of fooling. Is it abusive?"

Asked whether he endorsed what he retweeted, he said, the same had been sent to him by someone and he only retweeted it.

"I have said that this is not mine. But, could not help it."

"Not mine but couldnt help posting it. My apologies to the person concerned. He is the best in the "Art of Fooling!"," he said while posting a picture of Modi with the offensive tweet.

At the party briefing later, Congress media incharge Randeep Surjewala said, "Digvijaya Singh has already spoken about it and clarified the issue. I think there is nothing further to add in the matter."

BJP spokesman G V L Narasimha Rao lashed out at Singh, saying opposition leaders like him have "degenerated into abusive trolls" after repeated electoral drubbings.

Singhs "crass comments demonstrate the degeneration of a party that prides itself on a great legacy. These comments amount to insulting 130 crore people of India whose mandate is vested in the prime minister," Rao said.

"The Congress will have to publicly apologise for the filthy abuse of its front-ranking leaders who in the wake of repeated electoral drubbings have degenerated into abusive trolls on the social media," he said. PTI SKC KR RT SMN AKK AKK