A slightly amended version of a draft sanctions resolution was circulated Tuesday among the Security Council's 15 members, who also heard a briefing from the sponsors.

But after two informal bargaining sessions, envoys of the council's five veto-wielding members -- Britain, China, France, Russia and the United States -- plus Germany were still unable to find common ground on two key elements of the draft.

"We still have some difficult problems to resolve," Russia's UN Ambassador Vitaly Churkin told reporters, restated his opposition to the inclusion in the text's annex of a travel ban on 12 officials directly linked to Iran's nuclear and ballistic missile programs.

"We think it does not fit in the concept of the resolution, it's not going to help anything in terms of non proliferation, its just an unnecessary irritant," the Russian envoy added. "We'll meet tomorrow but I cannot tell you what tomorrow will bring."

Churkin also wants to reduce the scope of financial restrictions that would be placed on 11 entities involved in those programs.

"We have made progress but there are still two paragraphs which are not yet settled," France's UN ambassador Jean-Marc de La Sabliere told reporters.

"We will try again tomorrow...We'll be reporting back to capitals and looking again forward to resolving this issue as soon as possible and getting this resolution done this week," US acting ambassador Alejandro Wolff said.

Meanwhile a UN official said that some of the council's 10 non-permanent members were miffed at not being sufficiently consulted and at being presented with a fait accompli.

"We are still looking for an adoption of this resolution by the end of this week," de La Sabliere said.

In Washington State Department spokesman Sean McCormack kept the pressure on Tuesday, saying: "We want to see a (council) vote before the weekend."

"I think we're down to a couple of issues in the resolution," McCormack said after US Secretary of State Condoleezza Rice discussed remaining obstacles to agreement on Monday with her Russian counterpart, Sergei Lavrov.

The spokesman predicted a unanimous vote by the council following months of tough negotiations among six major powers that saw Russia and China, which have close economic ties with Tehran, repeatedly seek to dilute the sanctions.

Earlier Tuesday Lavrov said the latest revised draft under discussion in New York "largely reflects our approach".

The draft submitted by Britain, France and Germany would impose a mandatory ban on trade with Iran in goods related to its nuclear and ballistic missile programs and place financial restrictions on persons and entities involved in the sectors.

It demands that Iran "without further delay suspend all enrichment-related and reprocessing activities, including research and development and work on all heavy water related projects."

It calls for a report within 60 days by the head of the UN nuclear watchdog agency on whether Iran has complied with fully with UN demands and says it will terminate the sanctions "as soon as it determines that Iran has fully complied with its obligations" under relevant UN resolutions.

It warns that if Tehran refuses to comply, the council "shall adopt further appropriate measures under Article 41 of Chapter Seven" of the UN charter", a reference to economic sanctions only.

But Iranian President Mahmoud Ahmadinejad vowed Tuesday that Iran would respond with unspecified retaliation if the UN Security Council imposed the sanctions.

"The European countries should know that if they insist on preventing Iran's moves (in its nuclear work), we will consider this behaviour a hostile act and we will react in return," he said in a speech broadcast on state television.

Tehran spurned an August 31 UN deadline to freeze uranium enrichment, a process which can provide fuel for nuclear reactors but also, in highly refined form, material for the core of a nuclear bomb.

Western powers suspect the Islamic Republic is seeking to acquire a nuclear weapons capability under the cover of its civilian nuclear program.

Tehran insists its nuclear ambitions are entirely peaceful and aimed at generating electricity.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.