“[US Special Envoy for Iran Robert] Malley is in Vienna, he'll be returning to Washington pretty soon. Talks are ongoing and they will continue at a pace that's honestly appropriate to address the significance of the issues that are currently on the table,” Porter said.
She added that Malley will return to Washington for consultations at the end of the week.
Earlier in the week, Iran's lead negotiator, Abbas Araqchi, said that the fifth round of talks was difficult but unlikely to be the last.
Since April, Vienna has been hosting sessions of the commission on the JCPOA, as well as informal meetings in different formats. In late May, a fifth round of talks was begun.
Iran has scaled back its commitments under the JCPOA to produce purer uranium after the Trump administration quit the pact in 2018 and reimposed crippling sanctions on Tehran. Since that time, the US elected a new president, and talks on restoring the JCPOA were reinitiated.