The United Nations' Security Council on Monday unanimously approved a resolution endorsing the Iran nuclear agreement.

The vote was never in doubt, since it was just negotiated by the Council's five permanent members — Britain, China, France, Russia and the United States — as well as Germany.

But the vote is likely to further anger Republicans and even some Democrats in Congress who were calling on the Obama administration to give Congress a vote first.

The top Republican and Democrat on the Senate Foreign Relations Committee were demanding that Congress act first, and a key House Democrat, Minority Whip Steny Hoyer, D-Md., made the same demand last week.

Matthew Rycroft, Britain's representative to the U.N., called the agreement a "landmark achievement" that "gives us the chance to change the relationship between Iran and the Security Council… we can now start the work of rebuilding the deficit of trust."

Russian Ambassador to the U.N. Vitaly Churkin said the vote secures the right of Iran to continue a peaceful nuclear program and enrich uranium with a control by international inspectors.

"Today the Security Council has confirmed the inalienable right of Iran to develop a peaceful nuclear program including to enrich uranium while ensuring the comprehensive control by the IAEA," he said, referring to the International Atomic Energy Agency.

"The resolution guarantees the removal of the burden of sanctions on Iran and the framework of the implementation of the [Joint Comprehensive Plan of Action] through a clear and transparent mechanism, which will be made operational by concrete steps based on confidence in Iran and guarding its nuclear program," he said.