By Francois Murphy
VIENNA (Reuters) - The United States on Thursday threatened future action against Iran at the U.N. nuclear watchdog if Tehran keeps "stonewalling" the watchdog by denying it the cooperation and answers it seeks on issues including long-unexplained uranium traces.
At a quarterly meeting of the International Atomic Energy Agency's 35-nation Board of Governors, Washington again told Iran to cooperate with IAEA inspectors who for years have been seeking explanations from Tehran on the origin of uranium particles at undeclared sites.
The United States has stopped short, for now, of seeking a resolution against Iran, however. Diplomats have cited the U.S. presidential election in November as a reason Washington has been reluctant to do that. Tehran bristles at such resolutions and often responds by stepping up its activities.
"We believe we have come to the point that we and the broader international community must consider anew how to respond to Iran's continued stonewalling," the United States said in a statement to the Board meeting. "We cannot allow Iran's current pattern of behavior to continue."
It is now more than a year since the last Board resolution against Iran, which ordered it to cooperate urgently with the investigation into the particles. Tehran dismissed the resolution as "political" and "anti-Iranian" even though only China and Russia opposed it.
The United States and its three top European allies - Britain, France and Germany - again opted against seeking a resolution against Iran at this week's meeting but the United States said that if Iran did not provide the necessary cooperation soon, it would act.
"It is our strongly held view that Iran's continuing lack of credible cooperation provides grounds for pursuing further Board of Governors action, including the possibility of additional resolutions and consideration of whether Iran is once again in noncompliance with its safeguards obligations," it said.
In 2018 then-President Donald Trump pulled the United States out of a 2015 deal under which major powers lifted sanctions against Iran in exchange for restrictions on its nuclear activities. After sanctions were re-imposed, Iran expanded those activities far beyond the deal's limits.
It is now enriching uranium to up to 60% purity, close to the roughly 90% of weapons grade and far above the deal's cap of 3.67%. Western powers say there is no credible civil explanation for enriching to that level and the IAEA says no country has done so without producing a nuclear bomb.
Iran says its aims are entirely peaceful and it has the right to enrich to high levels for civil purposes.
The United States said Iran should provide the IAEA with cooperation including access "for the purposes of collecting environmental samples ... and it must begin to do so now".
If it did not, it would ask IAEA chief Rafael Grossi to provide a "comprehensive report" on Iran's nuclear activities more wide-ranging than his regular quarterly ones, it said.
"Then, based on the content of that report, we will take appropriate action in support of the IAEA and the global nuclear nonproliferation regime," it added.