Three months after the last meeting to negotiate a revival of the nuclear agreement between Iran and world powers, it remains unclear if and when the talks in Vienna will restart, or who might represent Iran’s new government.

In the interim, Iran has continued to expand the quantity and quality of its uranium enrichment, leading some experts to conclude it is now even closer to possessing enough fissile material to build a bomb than the two or three months the Biden administration has publicly estimated. At the same time, Iran has repeatedly sparred with the International Atomic Energy Agency over monitoring of its nuclear activities originally agreed in the 2015 deal.

For its part, the administration has continued to warn that negotiating time is running out, without saying how much time is left or what it will do if it expires.

“We don’t have a timetable,” a senior State Department official said. “Our position is that we’re ready to go back” to the table, although “at some point, that won’t be possible any more, because their nuclear advances will become irreversible, and it simply will not be feasible to go back the deal” as it was initially negotiated.

“We’ll know it when we see it,” said the official, speaking on condition of anonymity about the sensitive negotiations. “When we reach that point, we’ll have to assess where we are and how we proceed.”

Some answers may emerge this week when the Tehran government says Iran’s new foreign minister, Hossein Amir-Abdollahian, plans to hold bilateral meetings with his counterparts from Britain, Germany and France at the annual United Nations General Assembly.

Iranian Foreign Ministry spokesperson Saeed Khatibzadeh told reporters in New York on Tuesday that all were being told the Vienna talks would resume “in the next few weeks.”

In a prerecorded speech to the General Assembly later Tuesday, President Ebrahim Raisi said Iran “considers useful the talks whose ultimate outcome is the lifting of all oppressive sanctions,” but gave no indication of when the Vienna negotiations should restart.

Raisi devoted much of his relatively brief address to criticizing the United States and its sanctions policy, which he called a “new way of war with the rest of the world.” He repeated Iran’s long-standing insistence that nuclear weapons “have no place in our defense doctrine,” and are “forbidden” based on a religious decree by Ayatollah Ali Khamenei, the Iranian supreme leader.

Speaking about Afghanistan, Raisi joined much of the rest of the world in calling on the Taliban to include others in their government. “If an inclusive government having an effective participation of all ethnicities shouldn’t emerge to run Afghanistan,” he said, “security will not be restored to the country. And like occupation, paternalism is also doomed to failure.”