Security was increased at Union minister Nitin Gadkari's home and office in Nagpur on Tuesday after a man made three calls threatening to harm the senior BJP leader if Rs 10 crore was not paid to him, a police official said.

The caller identified himself as one Jayesh Pujari, alias Jayesh Kantha, the same person whose name had been used to make similar calls to the minister's office in January, he said.