Iran will not suspend its uranium enrichment to a level of 20%, a spokesman for the Foreign Ministry in Tehran declared Wednesday, in response to a letter sent by Russia, France and the United States to the United Nations nuclear watchdog.
"We will not review offers that would lead to the closure of the reactor in Tehran," Ramin Mehmanparast told the ISNA news agency.
The three powers' joint letter said that "Iran's move to escalate uranium enrichment is unjustified because a draft nuclear deal it has snubbed lists guarantees for Tehran's benefit."
The letter to UN nuclear watchdog IAEA was a response to Iran's launch last week of higher-grade enrichment – raising suspicions of a quest for atomic bomb capability – on grounds that world powers were imposing unpalatable terms for the deal.
"(This) is wholly unjustified ... If Iran goes forward with this escalation, it would raise new concerns about Iran's nuclear intentions," the letter said. It said the plan for Iran to swap enriched uranium for nuclear medicine fuel had legal assurances it would be fulfilled, contrary to Iran's assertions.
It said the UN proposal for Iran to swap enriched uranium for nuclear medicine fuel, which would defuse the risk of Tehran using the material for nuclear bombs, contained legal assurances it would be fulfilled, contrary to Iran's assertions.
Diplomats said the February 12 letter was leaked to refute Iranian statements this week that the powers had offered a new proposal to address Tehran's complaints about the plan, brokered by the International Atomic Energy Agency on October 21.
The letter was important also as a further signal of a hardening Russian line on Iran's nuclear defiance after years of buffering an important trade partner from stringent UN sanctions long sought by Western powers.
The Kremlin said on Tuesday Iran could face harsher measures if it failed to dispel fears abroad about its nuclear program.
The three powers' letter listed provisions that they said "provide assurances regarding our collective commitment" to carry out the deal, and Washington had offered "substantial political assurances" as well.
They said guarantees included the IAEA taking custody of Iran's nuclear material as part of the swap, a legally binding "project and supply" pact, and US-Russian-French backing for IAEA technical aid to ensure the Tehran nuclear reactor that produces isotopes for cancer treatment operates safely.