UN-Arab League special envoy Kofi Annan headed off Monday morning to a meeting with Syrian President Bashar al-Assad in Damascus, seemingly to discuss the final options of his wobbling peace plan, sources told Xinhua.

Annan, who flew in a day earlier, is also expected to meet with officials of the Syrian foreign ministry.

Annan recently offered a few suggestions on how to salvage the peace plan in an interview with Guardian, saying that Iran has a role to play in resolving the crisis, a suggestion rejected by the U.S. and its western allies.

Sources told Xinhua anonymously that Annan will head Monday afternoon to Iran to meet with officials there.

The latest Middle Eastern leg of Annan's tour is apparently meant to serve his latest suggestion, inviting Iran to join the efforts to resolve the 16-month-old unrest.

It is not immediately clear what Annan wants Tehran to do regarding the Syrian situation, but the move came after he expressed discontent with the international wrangling on the Syrian issue.

In his interview with French daily Le Monde on Saturday, Annan said the international community's efforts to bring the 16-months unrest in Syria to an end politically have failed. "The evidence shows that we have not succeeded."

He noted that the divisions between regional and world powers over how to resolve the Syrian issue are making the situation worse.

He also told Guardian that Syria will face a spreading civil war unless Russia, the West and the Arab states end their " destructive competition" over the Syrian issue.

"Russia does have influence and can encourage the Syrian government to implement fully the six-point plan and Security Council resolutions. But this task cannot be left to the Russians alone. I expect Iran to play a role. Those governments -- the U.S. and the Friends of Syria -- that have influence with the opposition should also play a role. If they continue with this destructive competition, everyone will lose," Annan told Guardian.

"They (the West) accuse the Russians of arming the (Syrian) government. The Russians accuse them of arming the opposition and flooding the place with weapons. This is instead of coming together to see what can be done," he said.

The intractable crisis in Syria has recently careened toward a sectarian conflict between the majority Sunni and the Alawati sect, to which Assad and the ruling elite belong. Such sectarian conflict has long been seen in the restive provinces of Idlib and Homs, while in the capital, assassinations and killings suggest the same momentum.