"I am astonished that anyone would suggest that I am pro-BJP. I have a 30-year paper trail of published writings on my idea of India and my profound belief in India's pluralism," Tharoor, a former minister in the previous UPA government and second term MP from Thiruvananthapuram, said in a comment on social networking website Facebook.

"Being receptive to specific statements or actions of BJP leaders does not remotely imply acceptance of the party's core Hindutva agenda. The PM pitched his appeal as a non-political one and I received it in that spirit. I am a proud Congressman and a proud Indian. In short, not pro-BJP, just pro-India," the former UN diplomat, said.

Tharoor had given a positive response to Modi's invitation to join the ambitious "Swachh Bharat" campaign but wanted it to be a sustained programme instead of "tokenism".

Responding to Modi's call, Tharoor had last week said he was honoured to accept the invitation to join the Clean India campaign.

Tharoor, who praised Modi on a couple of occasions earlier, however, said that he was not a fan of tokenism and the challenge would be to sustain it beyond a week of photo opportunity.

Modi had challenged nine persons including Tharoor to join in the Swachh Bharat campaign on the lines of ALS Ice Bucket challenge.

While the inclusion of Tharoor among the persons mentioned by Modi came as a surprise to many, Congress party had downplayed it.