The steps are vital if Iran wants to make space for diplomacy with the US, spokesman Matt Miller said on Tuesday.
The US and many of its western allies fear Iran's nuclear programme may be a cover for developing nuclear weapons, which Tehran denies.
It is the second time in recent days that the US has criticised Iran for barring IAEA inspectors assigned to the country, hindering the UN nuclear watchdog's oversight of Tehran's atomic activities.
“Iran must take de-escalatory steps if it wants to reduce tensions and create a space for diplomacy,” Mr Miller said.
“Just in the last few weeks, we've seen Iran take steps to undermine the International Atomic Energy Agency's ability to do its work.
“So if Iran really is serious about taking de-escalatory steps, the first thing it (could) do would be to co-operate with the IAEA.”
When asked if he was saying Iran must take all such steps sought by the US before Washington would agree to direct or indirect talks with Tehran, Mr Miller replied: “I am not saying that.”
The IAEA was responsible for verifying Tehran's compliance with the defunct 2015 Iran nuclear deal, under which it curbed its nuclear programme in return for the easing of US, EU and UN sanctions.
Attempts to revive that deal, abandoned by then-US president Donald Trump in 2018, collapsed about a year ago and Washington has been searching for a new way to get Tehran to restrain its activity.