During the 1990s, intelligence agencies began reporting that Iran might be secretly expanding its nuclear activities.
Iran insisted that its program was purely peaceful, meant for electricity and medical research.
But questions continued to grow.
Then in 2002, a major revelation shocked the international community.
Previously undisclosed nuclear facilities were revealed in Natanz and Arak.
The discovery triggered global alarm.
The United States accused Iran of secretly pursuing the capability to build nuclear weapons.
Israel strongly supported this view and began warning that Iran could eventually become a nuclear power.
The issue quickly became one of the most serious international disputes of the new century.