The United States on Wednesday responded to Iran's suggestions on reviving a 2015 nuclear deal as momentum builds to bring back the landmark agreement trashed by former president Donald Trump.
Just weeks after the deal looked dead, the European Union put forward on August 8 what it called a final text to restore the agreement, in which Iran would see sanctions relief and be able to sell its oil again in return for severe limits on its nuclear programme.
Iran came back last week with a series of proposed changes, to which the United States formally responded on Wednesday, a day after Tehran accused its arch-enemy of stonewalling.
Iran, the United States and the European Union all confirmed the US response, but none immediately discussed it in depth.
The US review on Iran's "comments has now concluded. We have responded to the EU today," US State Department spokesman Ned Price said.
In Tehran, foreign ministry spokesman Nasser Kanani said Iran has begun "carefully reviewing" the US response sent by the European Union.
"The Islamic Republic of Iran will announce its opinion in this context to the coordinator after it completes its review," Kanani added.
With signs that the agreement will reach the finish line, Iran's arch-rival Israel stepped up pressure on Western nations to block it.
"On the table right now is a bad deal. It would give Iran $100 billion a year," Israeli prime minister Yair Lapid told journalists Wednesday.
The money would be used by Iran-backed militant groups Hamas, Hezbollah and Islamic Jihad to "undermine stability in the Middle East and spread terror around the globe," he added.
Lapid, however, has promised to preserve cooperation with the United States, Israel's crucial ally, and has avoided the confrontational stance of former prime minister Benjamin Netanyahu, who openly joined then-president Barack Obama's Republican rivals to campaign against the deal when it was reached.
Israel's national security advisor Eyal Hulata was holding talks in Washington. His counterpart Jake Sullivan told him Tuesday that the United States was committed to "preserve and strengthen" Israel's defences and "ensure that Iran never acquires a nuclear weapon."
President Joe Biden took office with a goal of restoring the agreement, believing it was the best way to constrain Iran's nuclear programme and that Trump's withdrawal had done nothing but lead Tehran to accelerate its nuclear work.
But a year and a half of diplomacy trudged along slowly in Vienna, where Iran pressed hard and insisted on dealing only indirectly with US envoy Rob Malley, with EU mediators shuttling between hotels.
With the agreement bitterly opposed by Israel, US Republicans and some Iranian hardliners, both Washington and Tehran have gone into spin mode to present the other side as offering concessions.
The United States says that Iran has backed down on a key sticking point -- they had wanted Biden to undo Trump's blacklisting of the powerful Islamic Revolutionary Guard Corps as a terrorist group.
Biden has refused to do so and just Tuesday ordered air strikes in Syria said to target paramilitary fighters linked to the Revolutionary Guards, the clerical regime's elite ideological unit.
White House spokesman John Kirby said the strikes destroyed infrastructure including ammunition depots in "direct response" to an August 15 attack on the small contingent of US troops in Syria.
"We don't seek escalation but we remain prepared to respond to any on-going threat," Kirby told reporters.
Iran's foreign ministry denounced the attack as "terrorist" and denied the targeted groups were linked to Tehran.
Under a reported compromise worked out by the European Union, the United States will keep the terrorist designation but limit actions against outside actors that deal with the Revolutionary Guards, who have vast influence across the Iranian economy.
EU foreign policy chief Josep Borrell, in an interview Tuesday with Spanish television, indicated that other nations in the agreement -- Britain, China, France, Germany and Russia -- were fine with the suggestions offered by Iran.
Kirby said the United States remained adamant on another point of dispute -- that Iran cooperate with the UN nuclear watchdog to clear up suspicions about earlier work at three undeclared sites.