Iran Chief Negotiator Unexpectedly Leaves Vienna as Nuclear Talks Hit Standstill

Iran’s chief negotiator at the nuclear talks in Vienna unexpectedly returned home Monday night, prompting European officials to say negotiations were at a standstill.

Iranian officials said Ali Bagheri-Kani, who leads the Iranian negotiating team, would soon return to Vienna. Two Western diplomats said it wasn’t clear why Mr. Bagheri-Kani left or when he would return.

His departure comes after Russia’s Foreign Minister Sergei Lavrov and his Iranian counterpart discussed Moscow’s weekend demand that Washington provide it with written guarantees that Western sanctions on Ukraine wouldn’t harm future Russian-Iranian trade.

Mr. Bagheri-Kani’s sudden departure raises the prospect that the Vienna negotiations on reviving the 2015 nuclear deal, which have dragged on for 11 months, could fail. The 2015 agreement lifted most international sanctions on Tehran in exchange for tight but temporary limits on Iran’s nuclear program.

 “It is time, in the next few days, for political decisions to end the ViennaTalks,” Enrique Mora, the European Union official who chairs the talks, said on Twitter.

The talks are about the exact steps Iran and the U.S. would take to return into compliance with the 2015 deal. The U.S. left the nuclear deal under President Donald Trump, who said the pact wouldn’t stop Iran from obtaining nuclear weapons. Since then, Iran has expanded its nuclear work and now has almost enough highly enriched uranium to fuel one nuclear weapon.

U.S. and Iranian officials in recent days have said they had still not reached a final deal on restoring the agreement, with a couple of significant differences remaining, including over which sanctions Washington would lift to revive the deal.

On Friday, the chief British, French and German negotiators returned home.

Russia over the weekend further darkened prospects for an agreement when Mr. Lavrov demanded guarantees that U.S. and European sanctions imposed on Moscow over its invasion of Ukraine wouldn’t affect Russia’s future trade with Iran. Western officials said there was no way they would agree to sweeping sanctions exemptions for Russia because of the nuclear deal. U.S. Secretary of State Antony Blinken said Sunday Mr. Lavrov’s demands were irrelevant.

“If the final decisions are not taken in Washington and Tehran now, this agreement is in serious jeopardy,” said a senior Western diplomat on Monday. “By delaying these decisions, a window has been opened for Moscow to wreak havoc.”

Mr. Lavrov’s demands appeared to irk Iranian officials, who over the weekend said they were seeking clarification from Moscow. Iranian media on Monday cited Iranian Foreign Minister Hossein Amir-Abdollahian, saying that Iran “will not allow any external factor to impact the national interests for removal of the sanctions in the Vienna talks.”

On Monday afternoon, following a telephone call between Mr. Lavrov and Mr. Amir-Abdollahian, Russia published a readout that doubled down on its call for a restored nuclear deal to “ensure that all its participants have equal rights” to develop “cooperation in all areas” with Iran. Mr. Lavrov had called for written guarantees from Washington over the weekend to deliver that.

An Iranian readout of the call said Mr. Amir-Abdollahian stressed that Iran’s cooperation with any country, including Russia, shouldn’t be affected by sanctions.

U.S. and European officials had hoped to wrap up the talks last week. U.S. officials have said for some time that only a few days remained to complete the talks because Iran’s nuclear work had advanced so far that it may soon be impossible to re-create the benefit of the nuclear deal for Washington: keeping Iran months away from having enough nuclear fuel for a bomb.

Since serious negotiations on Iran’s nuclear deal began in 2013, the talks have weathered a number of external crises, including Russia’s earlier invasion of Ukraine in 2014; the Syrian conflict that united Iran and Russia against Western-backed rebels; and growing U.S.-China tensions.

However Western officials said last week that the conflict in Ukraine was increasingly leaking into the talks and that they feared the diplomatic window to complete a deal could shut quickly. They said Russia’s chief negotiator at the talks, Mikhail Ulyanov, was having to clear positions with Moscow far more frequently.

Late last week, Mr. Ulyanov presented a paper to Mr. Mora’s EU team, according to two diplomats, setting out demands for written guarantees that Russia’s tasks under the nuclear deal, including a uranium swap with Iran and work on Iran’s nuclear program, shouldn’t be undercut by Western sanctions.

U.S. and European officials have said that could be resolved but Mr. Lavrov’s demands for exemptions from sanctions that “damage our right to free and full trade, economic and investment cooperation and military-technical cooperation” with Iran could drive a hole through the Ukraine-driven sanctions on Russia.