Kerry in Riyadh as Saudi-Iran tensions simmer

US Secretary of State John Kerry arrived in Saudi Arabia on Saturday hoping for an easing of tensions between the Gulf kingdom and Iran.

Kerry was attending a joint meeting with his Saudi counterpart Adel al-Jubeir and other foreign ministers from the six-nation GCC.

The US chief diplomat is also scheduled to meet with top officials of the Syrian opposition ahead of UN-sponsored peace talks with the regime of President Bashar al-Assad.

He will hold talks with King Salman and his son, Deputy Crown Prince Mohammed bin Salman, who is the defence minister.

Saudi Arabia and some of its allies cut diplomatic ties with Iran this month after protesters there burned Riyadh's embassy in Tehran and a consulate in the second city of Mashhad.

The violence against Riyadh's missions occurred after the kingdom executed dissident Shiite cleric Nimr al-Nimr, a driving force behind anti-government protests.

Nimr was one of four Shiites put to death on January 2 alongside 43 Sunnis. All were convicted of "terrorism".

"We understand the Saudi anger over the attack on their facilities in Iran," a senior US State Department official said before Kerry's arrival.

"But we also understand that lessening tensions is an important objective not only for the United States but for the region".

Saudi Arabia and its Gulf neighbours perceive a lack of US engagement in the region, particularly in the face of what they see as Iran's "interference" in Yemen, Syria, Lebanon and elsewhere.

Those feelings crystallised with a historic international deal which this month lifted crippling economic sanctions on Iran in return for a scaling back of its nuclear capabilities.

Kerry has long sought to reassure his Gulf allies about the overtures to Iran, and will continue those efforts in Riyadh.