A senior Red Cross official acknowledged Thursday there are problems with the organization's efforts to collect and distribute uncontaminated blood, but he insisted the blood it supplies is safe.

Dr. Jeffrey McCullough, a senior vice president for the American Red Cross, told a House subcommittee the Red Cross was intensifying its efforts to ensure that blood from people with infectious diseases such as AIDS and hepatitis is not released. The Red Cross collects and distributes about half of the nation's blood supply.McCullough testified one day after the Food and Drug Administration threatened to pull the license of the Red Cross center in Portland, Ore. An FDA inspection there found that blood improperly tested for AIDS and hepatitis had been released.

"I want to be absolutely clear on this, we must do more," McCullough told the Energy and Commerce subcommittee on oversight and investigation. "I am not satisfied; we have not done enough and I am not finished."

But he said the fundamental question is: "If you are receiving Red Cross blood, can you feel confident about the quality and safety of that blood?"

"I believe the answer to that is, yes, you can," he said.

The subcommittee chairman, Rep. John Dingell, D-Mich., said that while "the blood supply is safer than it has ever been, I must point out that I still have doubts that it is as safe as it should and could be."

Both the FDA and the Red Cross said Wednesday that although the Oregon blood facility has problems, there was no evidence that contaminated blood was released for use by the public.

However, the FDA said records at the American Red Cross Blood Services Pacific Northwest Region center show that blood units "inadequately or improperly" tested for AIDS and hepatitis B "were released in a small number of cases."

The agency also said the center accepted blood from donors who were at risk of being infected with AIDS and hepatitis.

"None of these problems are known to have resulted in transfusion of HIV-infected blood into any recipient," the announcement said.