The Bharatiya Janata Party (BJP) also criticised the government's decision, questioning the reason behind the refusal of a probe if the prime minister was "clean".

In a latter to Anna Hazare, Minister of State in the Prime Minister's Office V. Narayanasamy said that allegations against the prime minister were only based on a leaked draft report of the Comptroller and Auditor General (CAG) and reports in the media.

"You have not produced proof in support of the allegations and have said yourself that you were not making the allegations," Narayanasamy said in a four-page letter sent Friday but released to media Saturday.

Narayanasamy said the final CAG report on coal allocation had not been presented to parliament yet and the government will respond to it after it is tabled.

"It is also known that CVC (Central Vigilance Commission) has directed CBI (Central Bureau of Investigation) that it should make a preliminary inquiry into coal block allocation on the basis of letter written by an opposition MP and some other people. CBI will conduct its probe independently. Your allegations and apprehensions about CBI are inappropriate and wrong," Narayanasamy said.

Manmohan Singh was in charge of the coal portfolio from November 2006 to May 2009.

Team Anna member Manish Sisodia Saturday slammed the government's response.

"The content of that letter is trying to prove that there is no corruption in the country and all the ministers and officers are working honestly, and we are unnecessarily creating a ruckus on the issue of corruption," he told reporters here.

Sisodia said that on one hand the CBI was investigating the case, and on the other hand the government has already declared that there was no irregularity in the allocations and all the rules were followed.

Fellow activist and Team Anna member Kiran Bedi tweeted: "PMO's Prise (sic) to Annajee on allegations made on PM+14 Ministers is absolutely wishywashy! On Camera admission by Fr (former) Coal Sect (Secretary) supports CAG! (Comptroller and Auditor General)".

BJP joined in the criticism.

"If the prime minister is clean, what is the problem in ordering a probe? We thought Narayanasamy will announce a probe, but they are only giving clarification and covering up corruption," BJP spokesperson Syed Shahnawaz Hussain told reporters here.

Narayanasamy also rejected Team Anna's demand for an independent probe against the cabinet ministers, saying there were "enough legal and constitutional structures available".

He also said the style of Team Anna's letter and "long and loose" allegations in it were not acceptable.

"I have regret to say that your statement that country's highest institutions such as the Supreme Court, high court, CAG etc. had made allegations (against the ministers) from time to time is not only unclear but is not worth being accepted," he said.

Narayanasamy also rejected Team Anna's allegation that CBI inquiry against Samajwadi Party chief Mulayam Singh Yadav had been "suppressed", terming it "inappropriate to the government" and "insulting to judiciary".

The letter was in response to Team Anna's May 26 letter that charged Manmohan Singh and 14 cabinet ministers of "massive corruption" and sought an independent investigation team comprising three retired judges to probe the charges.

Besides Manmohan Singh, Home Minister P. Chidambaram, Finance Minister Pranab Mukherjee and External Affairs Minister S.M. Krishna also figured in the 79-page document prepared by Team Anna.