Syrian peace talks were in disarray on Monday even before they began after a UN invite to Iran sparked a boycott call from the opposition and President Bashar al-Assad ruled out a power-sharing deal.

In an exclusive AFP interview, Assad said there was a "significant" chance he will seek a new term and called for the talks opening in Switzerland Wednesday to focus on what he called his "war against terrorism."

With two days to go to negotiations more than a year in the making, UN chief Ban Ki-moon sparked a furore Sunday by inviting Iran - a key backer of Assad - to take up a seat at the table.

Syria's main exiled opposition group promptly said it would shun the Geneva II conference, due to kick off in Montreux before moving to Geneva.

Louay Safi, spokesman for the Syrian National Coalition, announced on Twitter that the opposition would stay away "unless Ban Ki-moon retracts Iran's invitation."

Washington, London and Paris said Tehran would have to clearly and publicly support the idea of a Syrian transitional government if it wanted to attend.

But Iran insisted Monday it would join the talks, which are aimed at setting up a transitional government to find a way out of the civil war that has claimed 130,000 lives and made millions homeless.

A US State Department official said Monday that US has received messages from members of the Syrian regime who "want a way out" of the current brutal fighting.

Western powers have so far opposed Iran's presence on the grounds that Tehran had not accepted an initial communiqué adopted by major powers in Geneva in June 2012 calling for the creation of an interim government.

The accord at the so-called Geneva I talks made no mention of Assad's departure, something the Syrian opposition says is non-negotiable.

To add to the confusion, Russia, another Damascus ally and its biggest weapons' supplier, said Tehran's absence from the conference would be an "unforgivable mistake."

Chinese Foreign Minister Wang Yi will leave Beijing on Wednesday for the peace conference in Geneva and on Monday he put forward five principles for a political settlement of the Syrian issue during a press briefing with Chinese media.

First, the issue of Syria must be resolved through political means. Second, the future of Syria must be decided by its own people. Third, an inclusive political transition process must be promoted. Fourth, national reconciliation and unity must be achieved in Syria. Fifth, humanitarian assistance must be delivered in Syria and its neighboring countries.

If Tehran does attend, there will be 40 countries and a group of regional bodies at the opening meeting, the most intensive diplomatic effort yet to end the war.

AFP - Xinhua