VIENNA—A U.S. envoy accused Iran on Thursday of “systematically demolishing” a facility at the Parchin military site that United Nations nuclear inspectors want to visit as part of their investigation into suspected weapons research.

“Iran has been taking measures that appear consistent with an effort to remove evidence of its past activities at Parchin,” U.S. envoy Robert Wood told the 35-nation board of the International Atomic Energy Agency (IAEA).

He said it was “troubling that Iran is blatantly hampering the (IAEA’s) ability to carry out its mandate by systematically demolishing the facility that has been identified by the IAEA as meriting inspection at the Parchin site.”

READ MORE: Russia and China agree to criticize Iran’s nuclear defiance

Read more about: