The Indian Statistical Institute (ISI) Tuesday described as "untrue" the BJP's allegation that UPA presidential candidate Pranab Mukherjee's letter quitting as its chairperson was "fabricated".
"This is untrue. The letter is still in my custody. I know his signature. It cannot be forged," the Kolkata-based institute's director Bimal Roy told IANS.
Roy said Mukherjee had June 20 sent his resignation from the chairman's post to President Pratibha Patil.
"I received it on June 22," Roy said.
Mukherjee had filed his nomination for the country's highest office June 28.
"I even had a talk with Mukherjee on the issue before he filed his resignation," Roy said.
The Bharatiya Janata Party claimed Tuesday that the resignation letter was fabricated.
A controversy was raked up Monday when Mukherjee's opponent, P.A. Sangma's team demanded rejection of Mukherjee's nomination, alleging that he was holding an office of profit as chairman of the Indian Statistical Institute (ISI).
The ISI, an institution of national importance, had Monday clarified that Mukherjee had resigned from the post June 20.