UN-Arab League peace envoy Kofi Annan says he has had constructive talks in Damascus with Syrian President Bashar al-Assad.

Mr Annan has now arrived in Iran for talks with Syria's main ally in the region.

He said it was a ''positive'' discussion and that they ''agreed an approach which I will share with the opposition."

Mr Annan once again stressed the importance of halting violence and promoting political dialogue - the key points of the plan he put forward in April.

Syrian Foreign Ministry spokesman Jihad Makdissi said in a Twitter message: "In both meetings we reassured Annan of Syria's commitment to implement the 6-points Plan and hoped other side is mutually committed."

The UN and Arab League envoy is stepping up efforts to halt the carnage in Syria, which monitors say has cost more than 17,000 lives since it erupted in mid-March last year.

In a TV interview aired yesterday, Mr Assad accused Saudi Arabia, Qatar, Turkey and the US of supplying arms and logistical support to the rebels trying to overthrow him.

"We know that (Annan) is coming up against countless obstacles but his plan should not be allowed to fail, it is a very good plan," he told Germany's ARD network.

"The main obstacle (is) that many countries don't want (it) to succeed. So they offer political support and they still send armaments and send money to terrorists in Syria," Mr Assad said, according to a transcript of the interview, held in English.