An unidentified man made a threatening call on the landline number of Union minister Nitin Gadkari's official residence on Motilal Nehru road in New Delhi, the police said on Tuesday.
The call was received by a staff of Gadkari's office on Monday night.
The caller did not share his details and demanded to speak to the minister and threaten him, a senior police officer said.
"The caller spoke in Hindi and said 'mujhe mantri ji se baat karni hai, unhe threaten karna hai' (I want to talk to the minister and want to threaten him), and disconnected the call," he said.
The minister's office reported the matter to the Delhi police which is now investigating the matter.
"All call records details are being analysed. The accused had called on the landline number so we are trying to trace the number to get to the culprit. An enquiry is underway," the officer added.
Notably, the minister's office in Nagpur had received such threat calls on two separate occasions earlier this year.
A team of the National Investigation Agency (NIA) had gone to Nagpur on May 9 to conduct a probe into the matter. The calls were allegedly made by a murder convict, Jayesh Pujari alias Kantha, who was arrested from a jail in Belagavi, Karnataka, and booked under the anti-terror law UAPA, the police had said.