A Russian diplomat deeply involved in the Vienna talks to revive the Iran nuclear deal is bragging about his success in helping Tehran get “much more” in the way of American concessions than either he or his Iranian colleagues had anticipated. 

The Vienna negotiations to revive the 2015 Joint Comprehensive Plan of Action were widely expected to be concluded this week, but Moscow in recent days added conditions that seem likely to delay an agreement for at least another week. 

In a videotaped interview posted on Twitter today, Moscow’s ambassador in Vienna, Mikhail Ulyanov, a central player in the JCPOA talks, says, “Iran got much more than it could expect, much more.” Also, “realistically speaking, Iran got more than frankly I expected, others expected. This is a matter of fact.”

Diplomats of the JCPOA’s original parties — America, France, Britain, Communist China, Russia, and Germany — have been negotiating with Iranian counterparts since November over a return to the original deal. The American delegation, headed by President Biden’s envoy, Robert Malley, has no direct contact with its Iranian counterparts, as Tehran shuns face-to-face negotiation with what it calls the Great Satan. 

The Iranian and American delegations stay at the same Vienna hotel, but they rely on European, Russian, and Chinese intermediaries to relay messages. Such phone-tag negotiations leave a lot of room for Iran’s staunch allies — the Russians and the Chinese — to extract American concessions. The Russian envoy indicates he has used that mechanism to extract favors for Tehran.     

“Our Chinese friends were also very efficient and useful as co-negotiators,” Mr. Ulyanov said. “We could rely on each other on many, many points. And on many, many points through the joint efforts we succeeded. I can recollect dozens of such cases when on rather serious, significant questions we managed together to get positive results close to what we wanted to achieve.” 

Also, Mr. Ulyanov said, the “Iranian clerics are fighting for Iranian nuclear — national interests like lions. They fight for every comma, every word, and as a rule, quite successfully.”

The latest snag in the negotiations came Saturday, when Moscow’s foreign minister, Sergei Lavrov, added a new demand, saying as part of the renewed deal America must guarantee that sanctions it has levied on Russia for the Ukraine invasion would not apply to its trade with Iran. 

“We have asked for a written guarantee,” Mr. Lavrov said, “that the current process triggered by the United States does not in any way damage our right to free and full trade, economic and investment cooperation, and military-technical cooperation with the Islamic State.”

Washington is pushing back. Secretary of State Blinken told the Columbia Broadcasting System that Western sanctions on Russia have nothing to do with the Iran deal. “These things are totally different and are just not in any way linked together,” he said.

Moscow, however, is aware of the Biden administration’s desire to fulfill an election promise to return to the agreement that was dropped by President Trump in 2018, which is why Mr. Lavrov is pushing the envelope, trying to extract last-minute American concessions. 

In the interview with CBS, Mr. Blinken said that while a deal is close to completion, “nothing is done unless everything is done.” Regardless of the deal’s success, he said, it would not “prevent us from taking action against Iran when it engages in actions that threaten us [or] our partners.”

Meanwhile, Congress is pushing Mr. Biden to ban Russian oil and gas exports. So far, Washington has made sanctions exceptions for Russian energy exports. “The idea that we’re funding Putin’s war machine and quite frankly, genocide … that has to stop,” the ranking Republican at House Foreign Affairs Committee, Congressman Michael McCall, told CNN. 

Critics point to a dissonance between America’s attempt to exert such pressure on Russia while at the same time cooperating with Moscow to reverse Mr. Trump’s policy of putting “maximum pressure” on Iran.

In recent days, administration officials have pushed back on critics, indicating that a successful deal with Iran could offset rising prices in energy markets if sanctions deprive Russia of its ability to export oil and gas. 

That “disconnect,” says an Iran watcher at the Foundation for the Defense of Democracies, Behnam Ben Taleblu, is jarring. “The Biden administration is looking to sanction Russian oil while removing restrictions on the export and sale of Iranian oil,” he says. “Putin and Khamenei have and continue to use their energy resources to fund their domestic repression and foreign aggression.”