"We have no choice but to work, in the coming days and weeks, on a new sanctions resolution at the Security Council," French foreign ministry spokesman Eric Chevallier told a press conference.

The French warning follows a new report by the International Atomic Energy Agency (IAEA), the UN's atomic watchdog, that said Iran had not frozen uranium enrichment activities as instructed by the UN.

Chevallier described the report as "extremely worrying."

France belongs to a group of six world powers attempting to convince Iran to halt sensitive nuclear work with an incentives package in exchange for full suspension of uranium enrichment.

The US, wich fears Iran is trying to build a nuclear bomb, an accusation it rejects, told Tehran Monday that it faced possible new UN sanctions over its nuclear programme.

But China, a veto-wielding permanent member of the Security Council, argued on Tuesday that fresh sanctions would not resolve the stalemate.