The International Atomic Energy Agency (IAEA) says it suspects that Iran is conducting activities to develop nuclear weapons.

IAEA Director General Yukiya Amano stated Tuesday in a report that the nuclear agency received credible information that Iran has carried out activities relevant to the development of a nuclear explosive device.

The agency said in the report said that Iran is using uranium to make nuclear warheads and is using computers to conduct high explosive tests called “hydrodynamic experiments.”

The report detailed the agency has serious concerns regarding possible military dimensions to Iran’s nuclear program.

It also explained that after carefully and critically assessing the extensive information available to it, the agency found the information related to Iran’s nuclear development activities “credible.”