WATCH: Blinken meets with IAEA chief for talks on Iran nuclear activities

U.S. Secretary of State Antony Blinken welcomed the director general of the International Atomic Energy Agency, Rafael Grossi, to the State Department for talks Monday.

Watch the meeting in the player above.

The IAEA plays a key role in monitoring Iran’s nuclear activities, and Monday, Iran’s president said the United States should lift the sanctions on Tehran to prove it is serious about restarting stalled nuclear talks in Vienna.

Talks between Iran and European signatories of the 2015 nuclear deal, alongside Russia and China, have been stalled since June. Iran’s new administration, which took office in August, has not fixed a date for resuming talks. Iran has been resisting calls for a quick resumption of the talks in Vienna. Instead, Tehran wants to meet separately with the other parties to the deal in Brussels before returning to the table in Vienna.

As Blinken met Grossi, the State Department said the Biden administration did not believe a preliminary meeting in Brussels was needed. Blinken and others have warned that the window for diplomacy is closing.

The 2015 nuclear deal saw Tehran drastically limit its enrichment of uranium in exchange for the lifting of economic sanctions. Iran has insisted its nuclear program is only for peaceful purposes.

In 2018, then-President Donald Trump unilaterally withdrew America from the accord, raising tensions across the wider Middle East.

With the talks in Vienna now stalled, Iran has breached limits on its uranium enrichment set by the accord. It is now enriching small amounts of uranium at its closest-ever levels to weapons-grade purity and its stockpile continues to grow.