But the prime minister's statement failed to satisfy the opposition in parliament. In the Rajya Sabha, it triggered noisy protests leading to its adjournment.
Speaking a day before his departure to Russia to attend the G20 Summit, Manmohan Singh said it would be wrong to conclude that official papers sought by the Central Bureau of Investigation (CBI) in connection with the alleged irregularities in allocation of coal blocks were indeed missing.
"I would like to emphasize that the government is making all efforts to locate the papers requisitioned by the CBI and, at this stage, it would be premature to say that some papers are indeed missing," he said.
"A vast majority of the papers sought by the CBI have already been handed over to them.
"However, disregarding the factual position, some members have gone ahead and drawn their own conclusions that there is something fishy and the government is hiding something."
Manmohan Singh: "Let me assure this august house that the government has nothing to hide."
He urged MPs not to draw hasty conclusions and "let the house continue its normal business".
In 2006-09, a total of 204 coal blocks were allocated to state-run and private companies. Of these, licences of 40 blocks were later cancelled.
Coal Minister Sriprakash Jaiswal told parliament last month that a 189 documents related to the allocations were missing.
"The fact that more than 150,000 pages of documentation have already been handed over to the CBI clearly shows that our intention to facilitate the process of investigation cannot be called into question," Manmohan Singh said.
He said the government had cooperated with the Comptroller and Auditor General and the CBI from day one. "We will continue to do so."
"If the records in question are indeed found missing, the government will carry out a thorough investigation and ensure that the guilty are brought to book...
"The government shall follow directions (of the Supreme Court) in letter and spirit and do its best to locate and hand over the requisite papers to the CBI within the stipulate time," he said.
But Manmohan Singh's bid to end the continuing uproar in parliament over the missing files did not satisfy the opposition benches.
The Bharatiya Janata Party (BJP) and other parties said the prime minister had not responded to their concerns.
As Manmohan Singh left the Rajya Sabha, there were noisy protests by the opposition. Deputy Chairperson P.J. Kurien tried to restore order but failed, leading to its adjournment till 2 p.m.
BJP's Arun Jaitley demanded to know who would take "moral responsibility" over the missing files.
"There has been an attempt to mislead this house," he said.
"It has every conceivable element of bad governance as it involves fraud, contempt of court, breach of privilege, conflict of interest and destruction of evidence," said Jaitley.
He said there was a notion that the missing files won't see the "light of the day" as the names of important people were involved in the alleged irregularities in the allocation of coal mines.
Communist Party of India-Marxist's Sitaram Yechury said the government was staying away from registering a formal complaint regarding the missing files.
"Why strict action is not taken against officials who were responsible for losing the files?" asked Bahujan Samaj Party chief Mayawati.