Cohen

WASHINGTON (CNN) -- Secretary of Defense William Cohen said Tuesday that a Pentagon report found no documented evidence that U.S. forces used sarin nerve gas or tried to track down and kill American defectors during a covert mission known as Operation Tailwind during the Vietnam War.

Cohen presented the findings at a news conference that came in response to a now-retracted CNN report which claimed that U.S. troops used sarin during a 1970 operation in Laos.

Cohen ordered an immediate investigation after the story was broadcast on June 7, when CNN also claimed that Operation Tailwind was designed to track down and kill American defectors.

The Pentagon report found two key findings:

• No records or personal recollections were found to suggest that U.S. defectors were targeted in Operation Tailwind.

• No evidence was found that sarin was ever transported to Southeast Asia or was used in Operation Tailwind.

Independent investigation

The men who participated in Operation Tailwind

CNN retracted its story at the beginning of July. CNN News Group Chairman, President and CEO Tom Johnson said that an independent investigation had concluded that the report "cannot support" the claims made in the "NewsStand: CNN and Time" program.

The CNN report prompted an outcry among military veterans and raised probing questions from other journalists.

Two key CNN producers in the report, April Oliver and Jack Smith, were fired while senior producer Pam Hill resigned. Prominent correspondent Peter Arnett was reprimanded.

Smith and Oliver, however, stand by their story and have accused CNN management of caving in to pressure by the military.