Jordan appears set to take the traditional Arab seat on the UN Security Council after Saudi Arabia rejected the position in protest at the body's failure to end the Syria war and act on other Middle East issues, Western diplomats said on Friday.

The 193-member UN General Assembly elected Saudi Arabia last month to the Security Council for a two-year term from January 1, but in a surprise move, Riyadh declined the position a day after the vote.

While Saudi Arabia has made its decision known in a Foreign Ministry statement, it has not officially notified the United Nations. Most UN diplomats believe a formal letter needs to be received from Riyadh before a new election can be held.

Western diplomats, speaking on condition of anonymity, said it appeared Jordan had agreed to replace Saudi Arabia on the council, after dropping out of a race against Riyadh for a seat on the UN Human Rights Council.

Jordan's place on the Security Council would still need two-thirds approval by the General Assembly, diplomats said. The unprecedented move by Saudi Arabia to reject the Security Council seat and the emergence of Jordan as the alternative candidate has left diplomats scratching their heads.

Several UN diplomats have said Jordan would have been wary of replacing Saudi Arabia on the Security Council because it is so closely involved in key issues before the body. Jordan neighbors Syria and refugees who have fled more than 2-1/2 years of fighting in the civil war now represent one-tenth of Jordan's population.

"I don't think Jordan, to be honest, wants to be on the Security Council," said one senior U.N. envoy, speaking on condition of anonymity.

Jordan's U.N. ambassador, Prince Zeid Ra'ad Zeid al-Hussein, did not immediately respond to requests for comment. The Jordanian mission to the United Nations said Zeid had returned to Amman for a few weeks.

Jordan dropped out of the race for a seat on the Human Rights Council earlier this week, paving the way for Saudi Arabia to be elected to that body unopposed, in spite of widespread criticism of its rights record.

The UN General Assembly is due to elect new members to the Geneva-based rights body on Tuesday.

The Security Council is dominated by its five permanent members - Britain, China, France, Russia and the United States - which have veto power over its decisions.

To ensure diversity, the council's 10 elected members are made up of three from Africa, two from Asia-Pacific, one from Eastern Europe, two from the Latin American and Caribbean group, and two from the Western European and others group. Five are chosen each year to serve two-year terms.

Arab states are split between the Asia-Pacific and African regional blocs and there is an unofficial deal that at least one Arab nation is always represented on the Security Council.

Saudi Arabia was the Arab candidate from the Asia-Pacific bloc. Kuwait had put its hand up to be the next Arab candidate from the group and to run for the 2018-2019 term on the Security Council, which has led some diplomats to speculate that the Gulf US ally could be a capable replacement.

Arab countries have been trying to persuade Saudi Arabia to take up the Security Council seat.

"Kuwait forms part of the efforts currently being carried out to convince Saudi Arabia to reverse its decision," Foreign Ministry Undersecretary Khaled al-Jarrallah told state news agency KUNA on Thursday.

Saudi Arabia's UN ambassador, Abdullah Al-Mouallimi, called on Friday for "profound and comprehensive" reform of the UN Security Council that includes expanding its membership and "abandoning the veto system or restricting its use."

"The Security Council has failed to address the situation in the Palestinian and Arab occupied territories, an issue under consideration by the council for more than six decades," Al-Mouallimi told a General Assembly debate on Security Council reform.

"The Syrian crisis continues, with a regime bent on suppressing the will of its people by brutal force, killing and displacing millions of people under the watch and sight of a council paralyzed by the abuse of the veto system," he said.

Syrian ally Russia, backed by China, has vetoed three council resolutions since October 2011 that would have condemned Syrian President Bashar al-Assad's government and threatened it with sanctions.

Saudi Arabia has warned of a shift away from the United States in part over what it sees as Washington's failure to take action against Assad and its policies on Iran.

US Secretary of State John Kerry met King Abdullah of Saudi Arabia on Monday and praised the US alliance with Saudi Arabia as strategic and enduring, but strains in the nearly 70-year-old relationship were apparent.-Reuters