European officials are preparing to try and make another push to salvage the nuclear deal with Iran, offering to send senior EU negotiator to Tehran in an effort to reach an agreement, according to Western diplomats.

Enrique Mora, Brussels' negotiations coordinator, informed his Iranian counterpart that he was ready to return to Tehran to break the stalemate, the diplomats said while revealing that Mora was yet to receive an invitation.

The Vienna talks between major powers and Iran aim to revive the 2015 nuclear agreement and return the United States to it following Washington's unilateral withdrawal in 2018 under then-President Donald Trump, who accompanied his decision with the imposition of harsh sanctions on Tehran.

The Vienna talks, which also include the United Kingdom, France, Germany, Russia, and China, have been on hold since March 11, with officials saying at the time that the final draft was virtually complete.

However, one of the remaining points in the Vienna Talks was the removal of the Islamic Revolution's Guard Corps (IRGC) designation as a terror group. The terror designation means that criminal penalties would be imposed on anyone doing business with any individual or entity connected to the IRGC.

Iran demanded the removal of the IRGC's "terrorist" designation before negotiations proceeded, but bipartisan opposition in Washington and anger from Israelis in West Asia at the prospect of the removal of the designation prevented the US from proceeding through that.

Israeli Prime Minister Naftali Bennett and Foreign Minister Yair Lapid released a joint statement urging the Biden administration not to remove the IRGC off the US register of foreign "terrorist organizations."

The US administration was considering the removal of the IRGC from its terror blacklist in exchange for a commitment from Iran to "de-escalate" in the region, Axios reported in March.

Iran has been refusing to engage in direct negotiations with Washington until the lifting of sanctions, with Europe mediating between the two.

Mora visited Tehran in late March to try to resolve the issue over the foreign terrorist designation, though he did not reach any solution.

US officials have said President Biden will not be more lenient nor eliminate the conditions for lifting the designation, while the West blamed Iran for the debacle, making it clear that the talks could come to a close unless Iran offers a pathway through the diplomatic crisis.

The opening for the talks came during an April 23 call between Iranian Foreign Minister Hossein Amir-Abdollahian and his EU counterpart, Enrique Mora. The latter will be trying to persuade Iran to agree to a final accord and kick the issue does the line, diplomats are saying.

Diplomats stress that Tehran coming back with another demand for a US concession on another issue might be met with consideration, but they also say they cannot reformulate the whole deal.

The US stressed that even if it lifts the terrorist designation, the IRGC would still be under several US sanctions.

"The only way I could see it being lifted is if Iran takes steps necessary to justify the lifting of that designation," US Secretary of State Antony Blinken said last week in the Senate. "It knows what it would have to do."

Iran has been stressing that its nuclear program is purely for civilian purposes, while hopes for a deal remain slim. However, Washington seeks to revive the nuclear deal, because, as state secretary Blinken said, reviving the nuclear deal is still in the interests of the US.