New Delhi: Prime Minister Manmohan Singh said on Saturday any wrongdoers in a widening 2G scam, which is threatening his political survival, will be prosecuted.

In his first comments since the corruption scandal blew up, Singh told a leadership summit in Delhi that several investigating agencies were looking into the issue, which could potentially emerge as the country’s biggest graft cases and which is tarnishing the reputation of a Prime Minister long seen as India’s most honest politician.

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“As far as this particular allocation of the 2G spectrum is concerned (as) Parliament is in session, I would not like to make a detailed statement," Singh added, without giving details.

Singh has been asked by the Supreme Court to explain why he failed to swiftly probe his telecom minister Andimuthu Raja, who was sacked last week, over selling telecom licences too cheaply.

Singh also took no action after a senior opposition lawmaker asked the prime minister’s office in 2008 to investigate Raja.

A representative of the government is due to file an affidavit to the Supreme Court detailing the government’s response later on Saturday. The Prime Minister has asked India’s top legal official, the attorney general, to represent him at the apex court.

Senior members of the ruling Congress party have rallied around Singh, saying he has done nothing wrong and dismissed any rumours of the Prime Minister planning to resign.

The controversy has hit Mumbai’s stock market, sending telecom shares lower.

Raja is accused of selling 2G spectrum licences well below their value, potentially losing the state up to $31 billion in revenues, according to a CAG audit.

Raja has denied any wrongdoing and Singh said any one found guilty in the case would be prosecuted.

“There should be no doubts in anybody’s mind that if any wrong thing has been done by anybody, he or she will be brought to book," he said.

On Tuesday, the Supreme Court took the rare step of publicly criticizing Singh for “alleged inaction" in taking 16 months to decide if Raja should be charged and investigated.

Any investigation, and possible prosecution, into a minister must be approved by the Prime Minister, and in Raja’s case, Singh decided not to do anything since the issue emerged in 2008.

The scandal, however, was brought up again by opposition lawmakers when Parliament’s winter session opened earlier this month, and had disrupted proceedings since then, demanding a full investigation.

Last week, the Comptroller and Auditor General of India (CAG), an official watchdog, issued a report into the 2G licences sale, accusing Raja of a series of corrupt practices.

The opposition claims Singh failed to act because he feared upsetting his coalition partner DMK.

Singh told the business forum the government would gladly discuss the issue in Parliament.

“We are ready to discuss all issues in Parliament. We are not afraid of discussion in Parliament. It’s my humble request to all political parties to let Parliament function, we can discuss everything," he said.

The attorney general will present an explanation to the Supreme Court on Saturday, and on Tuesday will appear in person to answer questions over how Singh handled the request to investigate Raja.