The head of the United Nations' nuclear watchdog said Monday that Iran had still not handed over key information to his staff, and that his body's investigation into Tehran's atomic program could not continue indefinitely.
"Iran has yet to provide explanations that enable the agency to clarify two outstanding practical measures," chief Yukiya Amano told the International Atomic Energy Agency's (IAEA) Board of Governors in Vienna, echoing a report seen by Reuters last month.
The two measures relating to alleged explosives tests and other measures that might have been used for bomb research should have been addressed by Iran last August.
"The Agency is not in a position to provide credible assurance about the absence of undeclared nuclear material and activities in Iran, and therefore to conclude that all nuclear material in Iran is in peaceful activities," Amano said.
The West has related concerns that Iran wants to develop nuclear warheads. Tehran has vehemently denied those allegations, saying its nuclear program is entirely peaceful.
Amano added that the IAEA remains ready to accelerate the resolution of all outstanding issues, but "this process cannot continue indefinitely."
The United States and five other powers are seeking to negotiate an agreement with Iran to curb its nuclear program in exchange for relief from economic sanctions. They have set a March deadline for a framework deal and a June deadline for a final one.
The IAEA is likely to monitor any possible deal between Iran and the six powers in addition to its own investigation into Iran's nuclear program. Amano said he proposed a 1.8-percent increase to the body's $386 million budget given increased demand for its services.
He added that he remained seriously concerned about the nuclear activities of North Korea, which quit the nuclear Non-Proliferation Treaty in 1993. The IAEA has not had inspectors on the ground there since they were expelled by North Korea in 2009.