"How can Manmohan Singh remain Prime Minister when CBI is investigating and finding irregularities even in the preliminary probe?" Prasad asked, while addressing mediapersons at the state BJP headquarters here.
"There cannot be one set of rules for allies and another for the Congress Prime Minister and other ministers," he said.
Under the same UPA government, two DMK ministers -- Dayanidhi Maran and A Raja -- were forced to resign for their alleged role in the 2G scam, then why the same rule does not apply to the Prime Minister and other ministers on the coal block allocation issue, Prasad asked.
On Leader of Opposition in Lok Sabha Sushma Swaraj's demand for cancellation of coal blocks and impartial probe, Prasad said the BJP's stand is clear on the issue.
The government must first clear its intentions by cancelling the allocation of coal blocks and institute an impartial probe into the matter, he stressed.
When asked whether BJP would be ready for a debate in Parliament if its two demands are met, Prasad said, "the question is hypothetical."
"The Parliament is not just a place to debate but is also meant for accountability," he added.
The BJP leader demanded that Singh should clarify why some of the 'biggest scams since Independence' like the financial irregularities in Commonwealth Games projects, 2G spectrum allocation, land scam in the airport privatisation and the alleged irregularities in coal block allocation have happened with "alarming regularity" during his Prime Ministership.
Prasad also dismissed reports that BJP-ruled states were involved in the coal block issue.
