"Of course this is definitely the expectation because otherwise, as I've said, this positive, constructive environment will be in jeopardy and this whole peace might collapse," Iranian ambassador Ali Asghar Soltanieh told AFP in an interview.

The International Atomic Energy Agency's deputy director general for safeguards Olli Heinonen will visit Tehran next week to draw up a plan to resolve "outstanding issues" in an over four-year-old IAEA investigation of Iran's nuclear program, Soltanieh said.

This comes with Iran defying UN Security Council resolutions for it to suspend uranium enrichment, which makes nuclear reactor fuel but also atom bomb material, and to cooperate fully with the IAEA, which has unresolved questions about Iranian nuclear activities that could have military applications.

The Security Council has already imposed two sets of sanctions against Iran for its refusal to suspend enrichment.

The United States and its European allies plan to propose a third sanctions resolution.

But China's UN ambassador Wang Guangya on Tuesday urged the international community to boost diplomatic efforts to end the nuclear standoff with Iran, saying the time was not yet right for new sanctions.