By Evelyn Leopold and Irwin Arieff

UNITED NATIONS (Reuters) - The five veto-holding members of the U.N. Security Council failed again on Wednesday to reach agreement on how to rein in Iran's nuclear ambitions after a fifth round of negotiations.

Russia and China are resisting proposals from Britain, France and the United States for a council statement that would express "serious concern" about Iran's nuclear program and asks it to comply with demands from the International Atomic Energy Agency (IAEA). The statement does not threaten sanctions.

At the same time foreign ministry officials from the five powers and Germany are considering meeting in New York on Monday to review strategy, diplomats said. Russia had previously proposed such talks in Vienna, seat of the IAEA.

China's U.N. ambassador, Wang Guangya, said he and Russia still had problems with a proposal that the IAEA be asked to report to the Security Council within 14 days on what progress Iran had made toward meeting the U.N. nuclear watchdog agency's demands.

Both nations view the reporting requirement as shifting the focus of the Iran dossier from the IAEA to the Security Council, which has the power to impose sanctions. They would like any report on Iran's compliance to go directly to the 35-nation IAEA governing board.

"We are still discussing," Wang told Reuters at the close of the hour-long session at the U.S. Mission to the United Nations, adding that he did not consider the talks deadlocked.

Russia's ambassador, Andrei Denisov, a Chinese speaker, said only that a quote from Mao Tse-tung aptly described the situation: "Prospects are bright but the road is winding."

The negotiations shift to the full Security Council on Thursday when all 15 of its members are to meet for a second time to discuss the draft drawn up by France and Britain. Their first informal meeting took place on Tuesday at the French Mission to the United Nations.

STATEMENT OR RESOLUTION?

The draft statement also calls on Iran "to reestablish full and sustained suspension of all enrichment-related and reprocessing activities, including research and development" that the IAEA would verify.

It asks Iran to reconsider building a heavy-water nuclear reactor in Arak, which is more suitable for producing fuel for nuclear weapons than a light-water reactor.

A council statement needs to be approved by all 15 members, while a resolution requires nine votes in favor and no veto from any of the permanent members. If the impasse continues, the West could try to force Russia and China into the uncomfortable position of having to consider a resolution.

"Whether it is a statement or a resolution we haven't decided," Bolton said earlier.

"We're trying to hold the permanent five together first but reality is reality and time is an important factor, given that the Iranians continue to progress toward overcoming their technological difficulties in enriching uranium," he said.

The 10 nonpermanent members of the Security Council, which rotate for two-year terms, are: Argentina, Denmark, Greece, Japan, Tanzania, Congo Republic, Ghana, Peru, Qatar and Slovakia.