Chattanooga, Tennessee - Viral infections, including hepatitis, have been found in 16 patients exposed to contaminated equipment at Veterans Affairs medical facilities, a department spokeswoman said Friday.

So far, 10 colonoscopy patients from the VA medical center in Murfreesboro, Tenn., have tested positive for hepatitis, VA spokeswoman Katie Roberts told The Associated Press. In a later e-mail, she reported six patients at the VA's ear, nose and throat clinic in Augusta, Ga, tested positive for unspecified viral infections.

Roberts stressed that the source of the infections isn't known, but said the VA will make sure those who tested positive "get the best possible treatment."

"There's no way to scientifically, conclusively prove they contracted this due to treatment at our facility," Roberts said.

The number of reported infections could rise.

More than 10,000 veterans were warned to get blood tests because they could have been exposed to contamination at those two facilities plus a medical center in Miami. All three sites failed to properly sterilize equipment between treatments, and the problems dated back for more than five years at the Murfreesboro and Miami hospitals.

Roberts said the department doesn't yet have results from most of the veterans it warned.

A VA alert to patients said they "could have been exposed to body fluids from a previous patient."

Roberts said four Tennessee patients have tested positive for hepatitis B and six have tested positive for hepatitis C, which is potentially life-threatening and can cause permanent liver damage. No one has tested positive for HIV, she said.

According to a VA e-mail, only about half of the Murfreesboro and Augusta patients notified by letter of a mistake that exposed them to "potentially infectious fluids" have requested department blood tests.

Some veterans said they decided to seek tests from their private physicians, rather than the VA.

The public first became aware of problems in February, when the agency announced it had sent letters to about 6,400 patients who had colonoscopies between April 23, 2003, and Dec. 1, 2008, at Murfreesboro and to about 1,800 patients treated over 11 months last year at Augusta.

Roberts said the problem in Tennessee was discovered in December and an internal alert was issued.

This week the VA announced it sent letters advising 3,260 patients who had colonoscopies between May 2004 and March 12 at the Miami Veterans Affairs Healthcare System that they also should get tests for HIV, hepatitis and other infectious diseases.

"We feel that the risk of cross-contamination among patients is small, and many patients are at no risk whatsoever," Dr. William E. Duncan of the VA Health Administration said in an e-mail. "Since we cannot know which patients are at risk, we are notifying everyone we feel may possibly have been placed at risk."

Two weeks after a review of procedures and training at VA facilities nationwide, Roberts said the VA cannot yet say if patients at other locations were exposed to equipment that was not properly sterilized.

U.S. Rep Ileana Ros-Lehtinen, R-Fla., said VA officials told her and other members of Congress on Thursday that the Miami facility initially reported it was free from problems only to later backtrack.

Ros-Lehtinen said the details were disclosed by the VA in a closed-door meeting convened by U.S. Rep. Steve Buyer, R-Ind., the top Republican on the House Committee on Veterans' Affairs.

Joe Davis, a spokesman for the Veterans of Foreign Wars in Washington, said he has notified his 20,000 newsletter subscribers about the situation.

"We are obviously very concerned anytime anybody's health is at risk from going to see the doctor," he said Friday. "We believe the VA has done an adequate job in quickly notifying those veterans who might be affected."