Alan Greenspan defended his record as former head of the Federal Reserve, Wednesday, challenging critics who say he encouraged risky lending by keeping interest rates low for too long.

Greenspan spoke in front of the bipartisan Financial Crisis Inquiry Commission investigating the roots of the current financial crisis.

He said the Fed did not have the authority to regulate subprime mortgages that led to the housing collapse.

Phil Angelides, the Chairman of the Financial Crisis Inquiry Commission, asked Greenspan, "Why in the face of all that did you not act to contain abusive, deceptive subprime lending? Why did you allow it to become such an infection in the marketplace?"

Greenspan responded, "If the Fed, as a regulator, had tried to thwart what everyone perceived as a fairly broad consensus that the trend was in the right direction, home ownership was rising and that was an unmitigated good, then Congress would have clamped down on us."

The panel will issue a final report later this year.