United States Secretary of State John Kerry arrived in Saudi Arabia hoping to repair ties with America's longstanding ally, which have frayed over the Syrian conflict and US outreach to Iran.

Kerry was greeted on Sunday night in Riyadh by Saudi Foreign Minister Prince Saud Al-Faisal bin Abdulaziz al-Saud.

The top US diplomat is already on his second stop of an 11-day trip which has become an exercise in damage control, as regional turbulence stirs tensions with longtime US partners.

We will be there for Saudi Arabia, for the Emirates, for Qataris, for the Jordanians, for the Egyptians and others. We will not allow those countries to be attacked from outside. We will stand with them John Kerry, US Secretary of State

Saudi Arabia, locked in a decades-long rivalry with Iran, is concerned that proposed Syrian peace talks could leave a Tehran-backed government in Damascus and that a breakthrough in nuclear negotiations could see US-Iranian relations restored.

Earlier on Sunday, in Cairo, Kerry acknowledged that while there might be differences over "tactics" in ending the Syrian conflict, the end goal for the United States and its allies was the same - a transition of power.

Riyadh, one of the main backers of the Syrian opposition, was reportedly angered when US President Barack Obama last month put on hold threatened military strikes against Syrian President Bashar al-Assad's forces.

"There are some countries [...] that wanted the United States to do one thing in respect to Syria and we have done something else," Kerry acknowledged during a joint press conference with Egyptian Foreign Minister Nabil Fahmy.

But he insisted: "Those differences on individual tactics on policy do not mean a difference on [the] fundamental goal of the policy."

Kerry also said the United States would stick with its friends as they navigate the turmoil unleashed by the Arab Spring, which saw former US allies toppled in Egypt, Tunisia and Yemen and the rise of powerful new extremist groups in Libya and Syria.

"We will be there for Saudi Arabia, for the Emirates, for Qataris, for the Jordanians, for the Egyptians and others. We will not allow those countries to be attacked from outside. We will stand with them," he told reporters.

On Monday, Kerry is due to have his first meeting since becoming secretary of state with Saudi King Abdullah.