London ? Russia and China agreed today to join the United States and its European allies in voting to report Iran to the U.N. Security Council for resuming uranium enrichment work and failing to disclose all facets of its nuclear program to U.N. inspectors.

The accord appeared to represent a major diplomatic breakthrough for the Bush administration and the European Union, which suspect Iran of concealing a nuclear weapons program behind the cover of what it claims to be a civilian nuclear project.

Russia and China, which have huge financial stakes in Iran, had been resisting the vote, which is due to be held at an emergency two-day U.N. International Atomic Energy Agency board of governors meeting beginning Thursday in Vienna, Austria.

Their about-face underscored the depths of their frustrations with the hard-line Iranian President Mahmoud Ahmadinejad’s regime and made it likely that a majority of the 35-member IAEA board of governors would vote to haul the Islamic republic before the Security Council, which can impose economic sanctions.

Secretary of State Condoleezza Rice hashed out the accord in four hours of late-night talks with her counterparts from Russia, China, Britain, France, Germany and European Union officials who have been spearheading negotiations with Iran. The United States, Russia, China, Britain and France are the veto-wielding members of the U.N. Security Council.

The wording of a statement on the agreement was finalized today.

In the statement, which was released by the British Foreign Office, the ministers said they “shared concerns about Iran’s nuclear program and agreed that an extensive period of confidence-building was required by Iran.”