People chant slogans in a protest to condemn U.S. withdrawal from the 2015 Iran nuclear deal in Tehran, Iran, on May 11, 2018. (Xinhua/Ahmad Halabisaz)

Iran on Sunday dismissed Europe's offer for an informal meeting involving the US on the troubled 2015 nuclear deal, saying the time is not "suitable" as Washington has failed to lift sanctions.

The European Union's political director earlier in February proposed the informal meeting involving all parties of the Vienna deal, a proposition accepted by US President Joe Biden's administration.

Following Biden's election, the US, the European parties to the deal - France, Germany and Britain - and Tehran have been trying to salvage the accord, which granted Iran international sanctions relief in return for restrictions on its nuclear program.

The accord has been nearing collapse since former president Donald Trump unilaterally withdrew in 2018 and reimposed crippling sanctions as part of a "maximum pressure" campaign against Tehran.

"Considering the recent positions and actions of the United States and the three European countries, [Iran] does not consider the time suitable to hold the informal meeting proposed by the European coordinator," Iranian foreign ministry spokesman Saeed Khatibzadeh said in a statement.

Biden has signaled readiness to revive the deal, but insists Iran first return to all its nuclear commitments, most of which it suspended in response to the sanctions, while Tehran demands Washington take the first step by scrapping the sanctions.

"While we are disappointed at Iran's response, we remain ready to reengage in meaningful diplomacy to achieve a mutual return to compliance," a White House spokesperson said Sunday.

"We will be consulting with our P5+1 partners on the best way forward," the spokesperson added, referring to the group of the five permanent members on the UN Security Council, plus Germany.

The foreign ministry's statement is expected to come ahead of a quarterly meeting Monday of the United Nations nuclear watchdog International Atomic Energy Agency (IAEA) board of governors, which is likely to discuss Iran's recent restrictions of some nuclear inspections.

AFP