Iran’s Foreign Minister Hossein Amir-Abdollahian said on Sunday that an agreement is “close” in negotiations to restore the 2015 nuclear deal (Joint Comprehensive Plan of Action or JCPOA) between Tehran and world powers.

“We are close to an agreement in the negotiations,” Amir-Abdollahian said during a phone conversation with UN Secretary-General Antonio Guterres, according to a statement by the Iranian Foreign Ministry.

Iranian and US delegations in Vienna do not communicate directly; other participants in the talks act as intermediaries, passing messages between the two countries.

“We have passed on our proposals on the remaining issues to the American side through the EU senior negotiator, and now the ball is in the US court,” Iran’s top diplomat added.

If the Iranian account is to be believed, Guterres stressed the importance of the Vienna talks and expressed hope that the parties would soon reach an agreement.

An agreement has appeared close at hand on several occasions during the talks' progress, but discussions stalled last month when Russia demanded guarantees that international sanctions imposed following its invasion of Ukraine would not negatively impact its trade with Iran.

Russian Foreign Minister Sergei Lavrov later said Moscow had received the necessary guarantees from Washington on trade with Iran.

The JCPOA gave Iran sanctions relief in exchange for curbs on its nuclear program to guarantee that the Iranians would not be able to develop a nuclear weapon. In 2018, then-U.S. President Donald Trump withdrew from the agreement; now, under Pres. Biden, the United States seems poised to again roll back the sanctions.

Another issue causing friction between the U.S. and Iran was the latter's demand that the Islamic Revolutionary Guard Corps (IRGC) be removed from the Americans' list of terrorist groups. After appearing to acquiesce, the Biden administration has reportedly backtracked.