Saudi Arabia, in an unprecedented show of anger at the failure of the international community to end the war in Syria and act on other Middle East issues, said on Friday it would not take up its seat on the United Nations Security Council.
The kingdom condemned what it called international double standards on the Middle East and demanded reforms in the Security Council.
Riyadh's frustration is mostly directed at Washington, its oldest international ally, which has pursued policies since the Arab Spring that Saudi rulers have bitterly opposed and which have severely damaged relations with the United States, Saudi analysts have said.
Saudi Arabia has also been angered by a rapprochement between Iran, its old regional foe, and the United States, which has taken root since President Barack Obama spoke by telephone last month to the new Iranian President, Hassan Rouhani, in the highest-level contact between the two countries in more than three decades.
Citing the Security Council's failure to resolve the Israeli-Palestinian dispute, take steps to end Syria's civil war and to stop nuclear proliferation in the region, Riyadh said the body had instead perpetuated conflicts and grievances.
"Saudi Arabia ... is refraining from taking membership of the UN Security Council until it has reformed so it can effectively and practically perform its duties and discharge its responsibilities in maintaining international security and peace," said a Foreign Ministry statement issued on state media.
The conservative Islamic kingdom has traditionally avoided big political statements, preferring to wield its influence as world's top oil exporter, birthplace of Islam and chief Arab ally of the United States behind closed doors.
However, its anger at the international response to Arab issues, particularly the Syrian conflict, boiled over after Syria's President, Bashar Assad, escaped US-led military strikes in response to a poison gas attack in Damascus by agreeing to give up his chemical arsenal.
It is the second time this month that Saudi Arabia has made a public gesture over what it sees as the Security Council's failure to take action to stop the civil war in Syria that has killed more than 100,000 people.
Earlier this month, the Saudi foreign minister cancelled a speech at the UN General Assembly in frustration over the international inaction on Syria and the Palestinian issue, a diplomatic source said.
"The kingdom sees that the method and work mechanism and the double standards in the Security Council prevent it from properly shouldering its responsibilities towards world peace," the foreign ministry said in a statement carried by the state news agency, SPA.
Saudi anger coincides with a rift between another Washington and another of its key Middle East allies, Egypt. Egypt's Foreign Minister said relations were in "turmoil" after Washington moved to curtail military aid to Cairo in a row over the way the army overthrew President Mohamed Morsi of the Islamist Muslim Brotherhood.
Saudi Arabia was one of five countries elected by the UN General Assembly on Thursday to serve a two-year term on the 15-member UN Security Council.
The body, which has powers to authorize military action, impose sanctions and set up peacekeeping operations, has 10 rotating members. The US, China, Russia, France and Britain are permanent members which wield a veto.
The Saudi Foreign Ministry said it was unable to take its seat until reforms were introduced that would allow the body to resolve Middle East issues.
US-allied Saudi Arabia has been angry over what it says is the failure of the international community to help either Syrian rebels fighting to topple Assad or Palestinians seeking an end to more than four decades of Israeli occupation.
The Security Council has been split on how to handle the civil war in Syria, with Western powers pushing for stronger sanctions against Assad and Russia vetoing resolutions to that end. Saudi Arabia has backed the rebels in that conflict.
The Saudis, along with other Arab states, have also often criticized the United States for blocking international action to end the Israeli occupation of Palestinian lands seized in the 1967 Middle East war.