The Iranian Foreign Ministry on Saturday described the joint statement issued by the E3, the European troika comprised of Germany, France, and the United Kingdom, about the nuclear talks between Iran and major world powers as "unconstructive" and "regrettable".

"It is surprising and regrettable that, in a situation where diplomatic interactions and exchanges of messages are continuing... to finalize the negotiations the E3 would issue such an unconstructive statement," Iranian Foreign Ministry spokesperson Nasser Kanaani said.

Kanaani had said a few days ago that Iran could meet the energy needs of European countries if the parties to the Iran nuclear deal reach an agreement to revive the accord.

The diplomat underlined that the other parties using their political will and working constructively would culminate in a nuclear deal.

The European Troika voiced earlier on Saturday their "dissatisfaction" with Iran's demands in the Vienna talks aimed at reviving the Iran nuclear deal, formally known as the Joint Comprehensive Plan of Action (JCPOA).

Iran chose not to use a critical diplomatic opportunity and instead chose to continue escalating its nuclear program, the E3 said in a statement. "Iran's stance goes against its legally-binding international commitments and threatens the probability of the JCPOA working."

The JCPOA, the E3 added, cannot be used to enable Iran to avoid committing to its legally-binding international commitments, noting that Iran's rejection of entering the proposed deal would prompt the three European states to consult their allies on ways to respond to Tehran's "nuclear escalation".

Just weeks after the deal seemed to have died, the EU 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 program.

Iranian FM Hossein Amir-Abdollahian underlined that Iran has demonstrated its goodwill and seriousness in order to reach a strong and sustainable deal.

It is noteworthy that in late August, Iran's top diplomat Foreign Minister Hossein Amir-Abdollahian demanded that the IAEA drop the issue of what the Western parties claim to be "undeclared sites", as momentum builds to revive a 2015 nuclear deal.

The spokesperson for the Atomic Energy Organization of Iran, Behrouz Kamalvandi, described in late August the IAEA's demands from Iran as excessive, noting that these demands could be implemented due to West-led sanctions. 

In June, the IAEA's board of governors adopted a resolution censuring Iran for failing to adequately explain the previous discovery of traces of enriched uranium at three sites allegedly "not declared by Tehran" as having hosted nuclear activities.