Diplomats at the UN are working on a resolution proposing sanctions against Iran for its refusal to halt controversial nuclear activities.
The Security Council has reached agreement on North Korea
Officials from the UK, France and Germany are developing the draft text.
They aim to introduce the draft resolution to the UN Security Council next week.
But Iran's chief negotiator warned that a UN resolution would be counter-productive and push back any chance of an agreement.
Iran says its nuclear programme is peaceful, but Western countries fear that Tehran is trying to develop nuclear weapons.
The five permanent UN Security Council members and Germany have offered Iran economic and political incentives if it stops enriching uranium, a process which can produce the material for a nuclear bomb.
But Iran has refused, and missed a UN Security Council deadline at the end of August to suspend its enrichment work.
The UN Security Council has successfully passed a resolution imposing sanctions against North Korea following its test of a nuclear device, and diplomats are now hoping they can reach agreement over Iran.
But Russia and China - permanent members of the UN Security Council who have the power to veto decisions - are reluctant to impose sanctions against Tehran and want more talks.
Mr Larijani warned sanctions would "accentuate" the crisis
Meanwhile Iran's nuclear negotiator Ali Larijani has warned that any new Security Council resolution would "push further back the chance of an agreement".
"If the Europeans give into US pressure, the situation will radicalise in such a way that Iran will suffer the least and the West will suffer the most," he said.
He reiterated Iranian threats that if sanctions are imposed, international nuclear inspectors may be expelled.
Pursuing sanctions would "accentuate the regional crisis", he said.