WASHINGTON (AFP) - The United States (US) on Friday shrugged off a decision by its key Gulf ally Saudi Arabia to reject a seat on the United Nations (UN) Security Council, saying Washington would continue to work with Riyadh.

"That's a decision they have to make, of course," State Department spokesman Jen Psaki said, when asked about US reaction to the move.

Saudi Arabia rejected the seat on the UN Security Council in an unprecedented move on Friday, accusing the international body of "double-standards" and failing to act against the Syrian regime.

At least one analyst said the snub also reflected Riyadh's disappointment with the diplomatic opening between ally Washington and arch foe Iran, which it accuses of meddling in regional states.

"Clearly we think the UN Security Council has an important role they can play on a range of issues, and there's evidence just from six weeks ago," she said, pointing to a recent UN resolution to strip Syria of its chemical weapons.

"I understand different countries will have different responses, but we'll continue to work with them on issues that we share of mutual concern." Just a few weeks ago, the United States was also gnashing its teeth in frustration at the deadlock in the UN Security Council over Syria.

But talks between US Secretary of State John Kerry and his Russian counterpart Sergei Lavrov unlocked a deal over reining in Syria's chemical weapons, although vast differences still remain over how to end the civil war.