Following Tehran's announcement, ElBaradei said he hoped Iran's response would be positive as it was important for a new "era of co-operation".
The deal on Iran's LEU was brokered by the IAEA at a meeting involving all four countries in Vienna, Austria, at a meeting on Wednesday.
The IAEA deal requires Iran to send 1,100kg of low-enriched uranium, which is about 70 per cent of its stockpile, to Russia by the end of the year.
After further enrichment there, the uranium would be sent to France to be converted into fuel to be used in Iran's medical research programme.
The deal is believed to prevent Iran from developing nuclear weapons, as 1,000kg is the amount of low-enriched uranium needed to produce a single nuclear bomb.
Earlier on Friday, Bernard Kouchner, the French foreign minister, had said indications that Iran would sign up to the deal were "not positive".
"I do not know what the results in Vienna today are, but the signs we received [from Iran] this morning are not positive. It is a pity," he said.
"France hopes a peaceful solution ... will be found and accepted and that nuclear development is not used for military purposes. That much is clear."
ElBaradei set Friday as the deadline for the four powers to sign the arrangement after their meeting on Wednesday.
The US and its allies are hoping to secure Iran's approval to ease Western fears about Iran's suspected ambition to make a nuclear weapon - a charge Tehran denies.
The US will wait a few days for Iran's response to the offer, President Barack Obama's administration said on Friday.
"I think we can stretch things a few days," Ian Kelly, the US state department spokesman, said. "But we're not going to wait forever."
"This is a real opportunity for Iran to help address some of the real concerns of the international community about its nuclear program and at the same time still provide for the humanitarian needs of the Iranian people."
Iranian state television reported on Friday that Tehran wanted to buy nuclear fuel for a research reactor rather than accept the drafted plan, but did not officially reject the IAEA proposal.
"Iran is interested in buying fuel for the Tehran research reactor within the framework of a clear proposal ... we are waiting for the other party's constructive and trust-building response," a member of its negotiating team was quoted as saying.
Martin Navias, a defence analyst from London's Kings College, told Al Jazeera that nuclear powers such as France would be able to provide Iran with fuels for its research reactor.
"The problem is that Iran seems to be offering this in exchange for the present deal.
"What seems to be happening in Tehran is that the authorities are fearful that once that material is out of the country, it may not come back, or it may be held back in order to Iran. So they're getting cold feet about it."
Iranian opposition to the UN plan could be driven by concerns that it would weaken Iran's control over its stockpiles of nuclear fuel and could be perceived as a concession to the US.
Iran has reportedly called for responses to its own proposals on its nuclear programme, although details of this were not made available.
"Now we are awaiting a positive and constructive response on Iran's proposal from the other party on providing nuclear fuel for Tehran's reactor," Iranian state television quoted a member of Iran's team at the IAEA as saying.
A source close to Saeed Jalili, Iran's senior nuclear negotiator, told Al Jazeera's Nazanine Moshiri in Tehran that it will not agree to give away 75 per cent of its enriched uranium stockpile, which is recommended under the proposal.