Iran has let the U.N. nuclear watchdog inspect one of the two sites it agreed last week to grant access to after a protracted standoff, while Tehran’s stockpile of enriched uranium has risen further, quarterly reports by the agency said on Friday.

The International Atomic Energy Agency inspected one of the sites and took environmental samples there, one of the two reports obtained by Reuters said, referring to samples aimed at detecting traces of nuclear material that may have been present.

The agency’s inspectors will visit the other site “later in September 2020 on a date already agreed with Iran, to take environmental samples”, the report said.