Iran carried out secret nuclear activities with material not declared to the U.N. nuclear watchdog at three locations that have long been under investigation, the watchdog said in a wide-ranging, confidential report to member states seen by Reuters.

The findings in the “comprehensive” International Atomic Energy Agency report requested by the agency’s 35-nation Board of Governors in November pave the way for a push by the United States, Britain, France and Germany for the board to declare Iran in violation of its non-proliferation obligations.