There are new signs of Iran's defiant nuclear activity. An image from inside the Parchin military site appears to show an explosive containment chamber.
   
That chamber would be needed for nuclear arms-related tests, which United Nations' inspectors suspect Tehran has conducted.

An official from a country tracking Iran's nuclear program released the image to The Associated Press.

He would only say that his information was from a person who had seen the chamber.  

Iran has not confirmed its existence and denies such testing has occurred.

A former official from the International Atomic Energy Agency says he believes the image is accurate.