The director general of the U.N. nuclear watchdog, which is investigating whether Iran carried out work related to developing an atom bomb, visited a sensitive military site during a trip to the country, the agency said on Sunday.

One of the questions the agency is trying to answer is whether Iran carried out research in the past at the site, called Parchin, related to building a nuclear weapon.

"The director general visited the site of Parchin, together with the head of the Department of Safeguards, Tero Varjoranta," the International Atomic Energy Agency said in a statement.

By Reuters