Making a brief statement to reporters, he said the resignation does not imply any "wrongdoing".
"I have tendered my resignation to the honourable prime minister while thanking him for giving me the opportunity to be a part of his team. I have done so to put an end to an unnecessary controversy in a matter which is before the honourable Supreme Court and in which no adverse comments have been made against me in any manner whatsoever. My conscience remains clear and I believe that I will stand vindicated because divine justice ordains that truth and justice will prevail," Kumar said in a statement.
Kumar, who is under attack over vetting the CBI report in the probe into the coal block allocation scam, submitted his resignation on Friday.
He also said there are certain political decisions that are considered necessary and he did what the prime minister and the party high command thought was appropriate.
Asked whether he has been made a scapegoat, Kumar refused to comment but said he would rather let people form their judgment.
"People of this country, my friends who stood by me, many of you in media and my esteemed colleagues in the profession know me for what I am. I would rather let them make a judgment," he said.
He said his resignation papers, "by any stretch of imagination, imply any wrongdoing."
"There are certain political decisions that are considered necessary...no adverse comments have been made against me (by the Supreme Court) in any manner whatsoever. My conscience remains clear and I believe that I will stand vindicated," he said.
Kumar said whatever the prime minister and the party high command had deemed fit, "as a loyal foot soldier I have done and I am proud of the fact that I am a loyal foot soldier of the party."
Asked whether his resignation was an indication that Congress President Sonia Gandhi has lost confidence in him, the former law minister replied in the negative.
"I do not think I have lost the support of any leader," he said.
He rejected suggestions that the party’s decision to make him quit, along with Railway Minister Pawan Kumar Bansal, was 'unfair' on part of the prime minister.
"It is the prerogative of the prime minister to ask his colleagues when to resign and how to resign," he said.
Some supporters, who had gathered at his official residence, raised slogans in support of Prime Minister Manmohan Singh and Ashwani Kumar.
Kumar, in his resignation letter, had said he was resigning to put an end to "unnecessary controversy" and "public perception of any wrongdoing".
He maintained that the Supreme Court had not passed any strictures against him.
His exit from the Union Cabinet came after a controversy broke out over his meeting with the CBI director and charges of making changes in the agency's draft probe report on the coal-gate scam.
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