NEW DELHI - A satirical cartoon published here last week showed Indian Prime Minister Manmohan Singh holding up his hands and declaring, "I'm above all this." The next frame zoomed out to show Singh perched on the bow of the sinking ship of his government, in shark-infested waters representing a string of corruption scandals.

On Wednesday, India's scholarly, soft-spoken leader decided that lofty abandon was no longer a sustainable tactic, submitting to a rare hour-long grilling in a televised news conference that was broadcast nationwide.

Singh's message was twofold: that his coalition government is "dead serious" about rooting out corruption and that the news media, which have sought relentlessly for six months to expose corrupt government officials, should stop disparaging India.

"The impression has gone round that we are a scam-driven country and that nothing good is happening in our country," Singh said. "In the process, willy-nilly, I think we are weakening the self-confidence of the people of India."

Yet the 78-year-old Singh, who often sounded hesitant and defensive, did little in his appearance to restore confidence or burnish his country's reputation.

Allegations that the government may have lost as much as $39 billion in revenue in 2007 and 2008 after firms were awarded telecom licenses at rock-bottom prices in return for kickbacks have caused months of paralysis in Parliament.

As finance minister in the early 1990s, Singh was considered the architect of the reforms that unleashed the Indian economy's potential. In his first term as prime minister, he pushed through a civilian nuclear cooperation deal with the United States that underscored India's emergence on the world stage. But his second term has disappointed many.

The most serious accusation against Singh is that he failed to act decisively when warned about the telecom industry scandal, even reappointing the minister at the center of the controversy. The former telecommunications minister, Andimuthu Raja, was arrested this month.

Singh said he had trusted his ministers to ultimately decide about the license applications, and went on to defend his government. "Things are not entirely the way I would like them to be," he said, "but frankly, I have never thought of resigning, because I have a job to do."

His remarks did little to satisfy the opposition Bharatiya Janata Party. "Nobody for a moment has suggested that he is guilty of any personal misdemeanor," said the party's Arun Jaitley. "But his culpability is lack of political leadership, lack of assertion and lack of courage to stop corruption when it was taking place."