Britain, Germany, France and the United States told the International Atomic Energy Agency (IAEA) on Thursday further action would be needed on Iran if the country did not fulfil legal obligations and clarify issues over nuclear material.

"Iran needs to provide, without further delay, technically credible information on the current location(s) of nuclear material and contaminated equipment in relation to Turquzabad and Varamin," the four countries said in a statement to the IAEA board on Sept. 13.