Saudi Arabia rejected membership of the UN Security Council on Friday, a day after it was elected to the body, accusing it of "double-standards" in resolving world conflicts.

Saudi Arabia rejected membership of the UN Security Council on Friday, a day after it was elected to the body, accusing it of "double-standards" in resolving world conflicts.

"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 foreign ministry said.

"Therefore 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 responsibilities in preserving the world's peace and security," a statement said.

For the first time ever, Saudi Arabia won a seat Thursday on the 15-member council, which has a key role in dealing with world conflicts.

The foreign ministry pointed specifically to the nearly three-year civil war in Syria and the protracted Palestinian-Zionist conflict, as key reasons for its refusal.

"Failing to find a solution to the Palestinian cause for 65 years" it said, has led to "numerous wars that have threatened world peace."

Likewise, it said, "allowing the regime in Syria to kill its own people with chemical weapons... without confronting it or imposing any deterrent sanctions... is a proof of the inability of the Security Council to carry out its duties and assume its responsibilities."

The Saudi kingdom is a major backer of Syrian opposition armed groups, and permits for itself to support militant groups with weapons and mercenaries to fight the national army, but accuses the UNSC of not taking a critical role in the crisis.

Saudi Arabia was chosen by the 193-member UN General Assembly, along with Chile, Chad, Lithuania and Nigeria.

Security Council powers had cautiously welcomed Saudi Arabia's election.

"Having them on the Security Council allows you to debate those issues in a way which you can't if they are not on the council," said one UN diplomat.