Two Senate rebels jumped into Congress' cut-the-deficit competition on Tuesday, proposing to raise the age of Medicare eligibility to 67 and increase monthly premiums for millions of current beneficiaries.

"We can't save Medicare as we know it," said Sen. Joseph Lieberman, I-Conn., who authored the plan with Republican Sen. Tom Coburn of Oklahoma. "We can only save Medicare if we change it," he added in an apparent jab at President Barack Obama and congressional Democrats.

Democrats reacted with criticism of the proposal, which Coburn said was designed to rescue the financially imperiled program and help the nation confront a "wall of debt." Republicans betrayed no sign of support either.

If nothing else, the response underscored the difficulty of legislative free-lancing at a time the Obama administration and congressional leaders are struggling to negotiate a compromise that cuts future deficits and clears the way for an increase in the nation's $14.3 trillion debt.

Without a debt limit increase by Aug. 2, Treasury Secretary Timothy Geithner has warned, the government could default, risking calamity for the U.S. economy and serious effects worldwide.

Republicans walked out of bipartisan talks last week but nevertheless said negotiations had been fruitful. In the days since, Obama has stepped up his personal involvement in the effort.

A published report says federal regulators are preparing to issue subpoenas to Google and other companies as authorities gather information for a broad antitrust probe into the Internet search leader's business practices.

The Wall Street Journal reported Thursday that the Federal Trade Commission will issue subpoenas "within days," which would signal that it has opened a formal investigation.

The FTC is looking into whether Google abuses its dominance of Internet search to extend its influence into other lucrative online markets, such as mapping, comparison shopping and travel. Rivals complain that Google Inc., which handles two out of every three Internet searches in the U.S., manipulates its results to steer users to its own sites and services and bury links to competitors.

Google and the Federal Trade Commission refused to comment Thursday.

The European Commission and the Texas attorney general have already opened investigations into whether Google uses its enormous clout as a major gateway to the Internet to stifle competition online. The EU launched its investigation after competitors -- U.K.-based price comparison site Foundem, French legal search engine ejustice.fr and Microsoft-owned shopping site Ciao -- complained that their services were being buried in Google search results.