Saudi Arabia angrily rejected a UN Security Council seat Friday, accusing the UN body of "double standards" over the Syria war and other trouble spots in an unprecedented diplomatic broadside.
The Saudi snub sparked disarray at the Security Council. The oil-rich Gulf monarchy had only won the seat on Thursday at a UN General Assembly election.
Russia criticized the Saudis' "strange" decision but the conservative kingdom got a more understanding reaction from its western allies.
UN leader Ban Ki-moon said Saudi Arabia did not immediately send notification of its decision to reject the term due to start on January 1.
But senior UN envoys said they did not expect the Saudi government to reverse the decision, which was announced in an outspoken foreign ministry statement.
"Work mechanisms and double-standards on the Security Council prevent it from carrying out its duties and assuming its responsibilities in keeping world peace," the ministry said.
Saudi Arabia "has no other option but to turn down Security Council membership until it is reformed and given the means to accomplish its duties and assume its responsiblities in preserving the world's peace and security."
The government said "allowing the ruling regime in Syria to kill and burn its people" with chemical weapons is "irrefutable evidence and proof of the inability of the Security Council to carry out its duties and responsibilities."
Diplomats and analysts said the Saudi gesture was mainly directed at the United States, which first threatened a military strike against Syria then backed down and which has started a dialogue with Riyadh's arch-foe Iran.
"It is hard not to think that Riyadh's decision reflects an overall cooling of the US-Saudi relationship," Charles Dunbar, a professor at Boston University and former US ambassador in the Middle East and UN envoy on the Western Sahara conflict.
"Syria and Iran would seem to be the two most prominent reasons for the downturn in relations," he added.
"It is a cry of exasperation with Washington," said a UN diplomat.
The United States shrugged off the decision by its key ally.
"That's a decision they have to make, of course," State Department spokeswoman Jen Psaki said.
"I understand different countries will have different responses, but we'll continue to work with them on issues that we share of mutual concern."
Saudi Arabia was one of five nations elected by the UN General Assembly to a two-year Security Council term. The others were Chad, Chile, Lithuania and Nigeria. All had stood unopposed.
No country has ever won a council seat and then refused to take it up.
Saudi Arabia's UN ambassador, Abdullah Al-Mouallimi, gave several press interviews hailing the election after the result was announced.
But the celebrations had barely finished when the Saudi foreign ministry announced the withdrawal.
Diplomats highlighted how Saudi Arabia's Foreign Minister Prince Saud al-Faisal refused to speak or even hand out a copy of his speech at the UN General Assembly in September, in a show of anger over the international handling of the Syria conflict.
If Saudi Arabia maintains its stance, the Asia-Pacific group of nations would have to propose a new candidate for the UN General Assembly to vote on.
Amid the diplomatic disarray, the decision again highlighted international divisions over the Syria conflict.
The Security Council passed its first resolution on the civil war in September, when it ordered the destruction of President Bashar al-Assad's chemical weapons.
Russia and China have vetoed three other western-backed resolutions seeking to put pressure on Assad over the conflict, which the UN says has left more than 100,000 dead.
The Russian foreign ministry sharply criticized Saudi Arabia's "strange" argument on the council's record on Syria.
Russia and Saudi Arabia have a traditionally testy relationship made worse by the Russia's support for Assad while Saudi Arabia is a major backer of opposition rebels.
"We are surprised by Saudi Arabia's unprecedented decision," said a Russian foreign ministry statement.
"In this way, Saudi Arabia has excluded itself from collective work within the Security Council to support international peace and security."
It added: "The kingdom's arguments arouse bewilderment, and the criticism of the UN Security Council in the context of the Syrian conflict is particularly strange."
However, France said several countries share Saudi Arabia's frustration.
"We think that Saudi Arabia would have brought a very positive contribution to the Security Council, but we do also understand the frustration of Saudi Arabia," France's UN ambassador Gerard Araud told reporters.
"The fact is that the Security Council has been unable to act now for more than two years," he added.