WASHINGTON — Faced with exasperated lawmakers upset by shifts in bailout strategy, Treasury Secretary Henry Paulson launched a spirited defense Tuesday of his handling of the $700 billion program and expressed fresh reservations about tapping the pool for mortgage guarantees to relieve skyrocketing home foreclosures.

Members of the House Financial Services Committee grilled Paulson for not doing enough to help distressed homeowners and for failing to force banks that get some of the bailout money to specifically use it to bolster lending to customers, one of the prime reasons behind the rescue package.

"It is essential" that some of the bailout money be used to ease foreclosures, said the panel's chairman, Rep. Barney Frank, D-Mass., a key player in shaping the package that Congress passed and President George W. Bush signed into law Oct. 3.

Amid fits and starts in the administration's rollout and direction of the program, "I have to say at this point that public confidence in what we have done so far is lower than anybody would want it to be, to the point where it could be an obstacle to further steps," Frank lamented.

In a break with the administration, Federal Deposit Insurance Corp. Chairman Sheila Bair, made a fresh pitch for using $24 billion of the bailout pool to help Americans at risk of losing their homes. House Speaker Nancy Pelosi is urging Paulson to support the FDIC plan.

"As foreclosures escalate, we are clearly falling behind the curve," Bair warned the panel. "Much more aggressive intervention is needed if we are to curb the damage to our neighborhoods and broader economic health."

Although Federal Reserve Chairman Ben Bernanke told lawmakers that in cases of some home loans, the FDIC plan could saddle heavy costs on the government, he said it is still a "very promising approach."

While Paulson was resistant to using some of the bailout money to provide mortgage guarantees, he said the administration will look for ways to provide foreclosure relief.

Some Democrats also prodded Paulson to divert $25 billion of the bailout money to help Detroit automakers. Paulson, however, didn't budge in his opposition.

"I don't see this as the purpose" of the bailout program, which is intended to stabilize jittery financial markets and get lending flowing more freely again, Paulson told the panel.

The Treasury chief found himself on the hot seat just one week after he officially abandoned the original rescue strategy of buying rotten mortgages and other bad assets from financial institutions. That had been the main thrust of the plan Paulson and Bernanke originally pitched to lawmakers.

Focusing the bailout program on infusing billions into banks — and possibly other types of companies — to pump up their capital and bolster lending to customers was deemed a faster and more effective approach to stabilizing the financial system than the original centerpiece of the plan, Paulson said.