RIYADH • Gulf monarchs began arriving in Saudi Arabia yesterday for a summit amid challenges, including plunging oil revenues, war in Yemen, pressure for peace in Syria and signs of regional divisions.

The kings and emirs are expected to voice support for a bid to unify Syria's opposition ahead of potential talks with President Bashar al-Assad's regime.

The Syria meeting, bringing together representatives of political and armed opposition factions, began separately earlier in the day.

The annual Gulf Cooperation Council (GCC) summit comes days before Yemeni rivals are to gather in Switzerland to try to end a costly war that has drawn in Gulf nations.

The GCC groups Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates.

Despite the urgency of the challenges facing the six countries, analysts say the Gulf monarchs will struggle to find common ground.

"This summit comes as the Gulf is witnessing one of its most critical years," said Mr Farea al-Muslimi, a visiting scholar at the Carnegie Middle East Centre.

He sees "internal disagreement" among the Gulf states which are confronting complicated economic and security challenges.

These include greater worries about Iran after a July deal between Washington and Teheran that will ease sanctions on the predominantly Shi'ite nation, including its oil sector, in return for restrictions on its nuclear facilities. Iran and Sunni-dominated Saudi Arabia are rivals for regional influence in Yemen, Syria and elsewhere.

The GCC was founded to more deeply integrate the Gulf countries but the emphasis over the past few years has been on intelligence and security cooperation, said Ms Jane Kinninmont of the Chatham House think-tank in London.

Low oil prices "should focus the minds of GCC leaders" on economic matters, in line with the wishes of many Gulf citizens, she said.

Crude prices have more than halved since early last year.

AGENCE FRANCE-PRESSE