VIENNA (Ruptly) — A meeting to revive the Joint Comprehensive Plan of Action (JCPOA) following what Tehran deemed was “an attack” on the Natanz nuclear plant took place in Vienna on Thursday.

The first round of indirect talks on a potential U.S. return to the Iran nuclear deal kicked off in Vienna on April 6, with both Tehran and Washington making positive comments about the efforts, with discussions set to resume on Wednesday.

While Joseph Biden’s administration has expressed its willingness to return to the 2015 deal, which Washington pulled out of under the President Trump government, timing has remained a point of contention between the U.S. and Iran.

Tehran has insisted on the full removal of all sanctions prior to it returning to compliance, while the U.S. has demanded that Iran return to the limits put in place under the deal first.