Prasad said the Congress President and Prime Minister of Pakistan, Imran Khan, are using the same language to target Modi over the controversial Rafale jet deal.
Prasad reiterated that for the first time in independent India, the President of a national party has used abusive language against the Prime Minister.
"Gandhi's statement was irresponsible and far from the truth. He should stop playing with national security. Rahul is helping Pakistan by repeatedly asking about the cost of Rafale aircraft."
Prasad's remarks come a day after Gandhi termed Modi a "thief" and "corrupt," citing the Rafale deal.
The Opposition has cornered the Modi government on the politically-charged Rafale deal after former French president Francois Hollande's reported remarks that the Indian government had proposed the name of Anil Ambani's Reliance Defence as the Indian partner for Dassault Aviation, the makers of Rafale.
Meanwhile, Pakistan has also jumped into the controversy to say the Modi government has cancelled the foreign ministers' level talks with because it wanted to "distract people's attention" from the Rafale deal.
In a tweet on Saturday, Pakistan's Federal Minister for Information, Fawad Hussain said: "We reject war mongering by ruling elite of India everyone know Indian Govt strategy is to use hate mongering against Pak basically to bail Pm Modi from call for resignation post French jets Rafael deal and divert attention of Indian public from this mega corruption scandal."
India on Friday cited the "brutal" killing of a BSF jawan along the International Border as well as the release of the postal stamps "glorifying" Kashmiri militant Burhan Wani for calling off the meeting between External Affairs Minister Sushma Swaraj and her Pakistani counterpart Shah Mehmood Qureshi.
External Affairs Ministry Spokesperson Raveesh Kumar had said that the incidents "exposed" the "true face" of Pakistan's new Prime Minister Imran Khan to the world as well as Islamabad's evil agenda behind the proposal for talks.
"The latest brutal killings of our security personnel by Pakistan-based entities and the recent release of a series of 20 postage stamps by Pakistan glorifying a terrorist and terrorism confirm that Pakistan will not mend its ways," Kumar said.
(With inputs from agencies)