Foreign ministers from the major powers have agreed to refer Iran back to the UN Security Council for possible punishment over its nuclear programme.
Iran denies claims it is trying to make atomic bombs
The decision by the Security Council's five permanent members plus Germany could lead to economic sanctions.
Ministers meeting in Paris said Tehran has not signalled it was seriously considering incentives designed to get it to abandon uranium enrichment.
But any threats of punishment by the UN would not include military force.
Uranium enrichment produces fuel for power plants or weapons.
Iran allowed to buy spare parts for civilian aircraft made by US manufacturers
Restrictions lifted on the use of US technology in agriculture
Provision of light water nuclear reactors and enriched fuel
Support for Iranian membership of World Trade Organisation
From Western diplomatic sources
Iran denies claims - by the US and some other countries - that it is trying to make atomic bombs and insists it has a right to enrich uranium for civilian purposes.
"The Iranians have given no indication at all they are ready to engage seriously on the substance of our proposals," French Foreign Minister Philippe Douste-Blazy said.
"We have no choice but to return to the United Nations Security Council," he said, speaking on behalf of the US, China, Russia, Britain, France and Germany.
The decision by China and Russia to back the statement appears to be a diplomatic victory for the US, the BBC's Hugh Schofield in Paris says.
Both countries, however, have said they oppose the toughest sanctions on Iran.
In New York, US Ambassador to the UN John Bolton said he hoped for council action early next week on a resolution demanding that Iran suspend all enrichment, as required by the International Atomic Energy Agency.
If Iran does not comply with that resolution, it could face harsher action.
The Paris statement did not give any specifics, but it cited a section of the UN charter that could open the door to economic sanctions.
Iran was referred to the Security Council earlier this year, but work on a UN resolution was suspended in May to allow the Iranian leadership to respond to the package of incentives.
The six powers want a pledge that Iran will abandon uranium enrichment, in exchange for the incentives.
Talks between Mr Larijani and Mr Solana were 'disappointing'
Ministers in Paris were briefed by the EU's foreign policy chief, Javier Solana.
Mr Solana met on Tuesday with Iran's chief negotiator, Ali Larijani, but the talks were disappointing, according to Mr Douste-Blazy's statement.
The major powers had told Iran they wanted a clear response to their offer of incentives before this weekend's summit of the G8 group of industrialised nations.
But Tehran has insisted it will not be rushed into an answer on the package on offer.
The incentives include offering Iran a state-of-the-art reactor with a guaranteed fuel supply and economic benefits if it halts uranium enrichment.
Earlier, the UN secretary general Kofi Annan urged Tehran to signal it was seriously considering the proposals.