The laboratory technician who may have been exposed to Ebola in a mishap last week at the Centers for Disease Control and Prevention in Atlanta is showing no signs of the disease, the U.S. Ebola co-ordinator said on Sunday.

"Only one technician was exposed. So far she's showing no signs of having the disease. She's being monitored every day," Ron Klain, named by U.S. President Barack Obama in October to lead the American response to Ebola, told CBS's Face the Nation.

The unidentified technician may have been exposed last Monday when working with Ebola specimens that were supposed to have been inactivated but which may instead have contained live virus, CDC has said.

The technician will be monitored for signs of infection for a total of 21 days, the disease's incubation period.

Klain called the mishap "unacceptable" and said CDC Director Dr. Tom Frieden had promised a report in four weeks on the investigation into the incident.

Klain said there had been no risk to the public or the larger CDC campus from the possible exposure.

3rd incident this year

The error follows two high-profile cases of mishandled samples of anthrax and avian influenza at the CDC earlier this year that called into question safety practices at the highly respected research institute.

Klain, who visited the CDC lab in October, said it has been studying Ebola for 20 years without incident and has processed more than 10,000 samples of the virus during the current outbreak, which has killed more than 7,500 people in West Africa.

"The American people should be very proud of the job that is being done in Atlanta by Dr. Frieden and the team at CDC," he said.

Two nurses in Dallas who treated an Ebola patient from Liberia are the only people known to have become infected with the disease on U.S. soil. They both recovered.