A senior member of the Saudi royal family has attacked the US over its policy on Syria, and called for a UN resolution to pull "Iraqi and Lebanese Shi'ite militia" out of the Middle Eastern country.

Prince Turki Al-Faisal, a former intelligence chief and an outspoken critic of President Barack Obama's administration since it started secret nuclear talks with Iran, said the world was disappointed with the "sense of no direction" in US foreign policy.

"I want the Americans to go to the Security Council and get a resolution that forces should be deployed to stop the fighting in Syria," he told the World Economic Forum in Davos. "If that is not available, then at least a humanitarian corridor to allow people not to starve."

Saudi Arabia and Qatar have backed the main Sunni Muslim opposition Syrian National Coalition and the Free Syrian Army with weapons, training, money and military intelligence in the fight against President Bashar al-Assad's government.

Iran has been one of Assad's biggest supporters in a conflict that has killed more than 130,000 Syrians and forced more than 2 million to flee.

Western countries have so far held back from providing rebels with heavy arms such as anti-tank weapons and missile launchers for fear they could fall into the wrong hands.

Prince Turki said Iraqi militia and Lebanese Shi'ite Hezbollah fighters outnumbered radical Sunni militants fighting in Syria.

"I'm not saying Sunnis should go fight," he said. "You have to get these (Shi'ite) people out. The only way to do it is by a concerted international effort led by the United States and supported by the US allies to force these people to stop the fighting."

Saudi Arabia, a historical US ally, has been dismayed that Washington worked behind its back to thrash out an interim agreement granting Iran limited sanctions relief in exchange for temporary restraints on Tehran's nuclear programme.

Riyadh, like Western countries, believes that drive is aimed at producing weapons - a charge Iran denies.

Asked whether Saudi Arabia has been blindsided, Prince Turki said: "Absolutely. On the Syria issue among other things, the (US) policy hasn't been clear and definitely the actions have not been clear either. This disturbs America's allies because we've grown to depend on America."

"It is not just about Iran (and) Syria, it's the sense of no direction," he said.

On a separate panel in Davos, Iran's foreign minister, Mohammad Javad Zarif, said he had met Prince Turki earlier on Friday without giving further details, a rare contact between the two Middle Eastern rivals.

"We want good relations with our neighbours. People should not be concerned," Zarif said.

"We have governance problems in the region. We have confidence problems in the region. We have a mentality in the region that sees the problems of some country its own assets. We need to change this mentality."

Asked whether Assad should leave, he said that it's a decision that Syrians should take.

"Extremism is a product of foreign intervention and product of short-sightedeness. Those who created the Taliban ended up paying their blood for what they have created. The flames that have been created in our region will engulf everybody." - Reuters