Iran has sent a message to EU foreign policy chief Javier Solana, but not a response to the latest proposals on its nuclear programme, officials have said.
A source within the Iranian Supreme National Security Council told the AFP news agency that the message was "not Iran's response to the six countries".
On Monday, the US and UK said Iran faced further sanctions if it did not respond positively to the proposals.
The move follows "inconclusive" talks between the EU and Tehran.
Mr Solana had given Iran's chief nuclear negotiator, Saeed Jalili, until last Saturday to respond to an offer not to impose further economic sanctions in return for a freeze on its uranium enrichment programme.
Mr Jalili said Iran would issue a formal written response on Tuesday.
The Iranian government insists its nuclear programme is for entirely peaceful purposes, while the US and its allies believe it could be used to develop nuclear weapons.>>>
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