France is among world powers trying to revive a 2015 nuclear deal with Iran that the previous U.S. administration quit and which Israel opposed, deeming its caps insufficient.

Foreign Minister Hossein Amir-Abdollahian had said Iran was "serious" about finalising a deal in Doha, but that it wouldn't cross its "red lines".

Tehran for its part said its focus was on sanctions relief, not directly mentioning the nuclear deal.

Russia played a key role in that deal, taking charge of Iran's excess enriched uranium stocks beyond those permitted under the agreement.

The US decided again to prolong and delay the agreement and went to the (IAEA) board of governors meeting with the delusion of using leverage

The United States is pursuing the path of meaningful diplomacy to achieve a mutual return to compliance with the Joint Comprehensive Plan of Action

The Guards accused "Zionists" of being behind the high-profile assassination and vowed revenge.

"We urge Iran to heed the call of the international community to fulfil its legal obligations, and cooperate with the IAEA to fully clarify and resolve issues without further delay."

IAEA board of governors meeting in Vienna likely to adopt anti-Iran resolution

A deal was reached about two decades ago to allow Iran to supply Oman with gas, but the project never materialised.

"The political cost Biden will pay for lifting sanctions on the IRGC is high, but it pales in comparison to the threat of a nuclear-armed Iran," Davenport said.

Israel has significantly increased its readiness level and has taken steps throughout the past year to prepare a credible military option against Iran’s nuclear facilities.