The UN's special envoy on the Syrian crisis is seeking to build support for his peace efforts with the leaders of Iran and Iraq, saying President Bashar al-Assad has agreed to a plan to quell the bloodshed in the most violent areas of Syria and then expand the operation to the whole country.

Top diplomat Kofi Annan said at a news conference in Iran that the plan still must be presented to the Syrian opposition. But he said his talks with Assad a day earlier focused on a new approach to ending the violence, which activists say has killed more than 17,000 people since March 2011.

"(Assad) made a suggestion of building an approach from the ground up in some of the districts where we have extreme violence — to try and contain the violence in those districts and, step by step, build up and end the violence across the country," Annan told reporters in Tehran, his first step on a tour of Syria's allies. He did not elaborate on the plan.

Annan later visited Iraq and met Prime Minister Nouri al-Maliki to discuss ways to end the fighting.

"I think we've all watched the tragic situation in Syria, the killings, the suffering of the people," Annan said in Baghdad.

"And everyone I've spoken to shares the concerns and the needs for us to stop the killing."

Allies in Russia, Iran and China

The conflict in Syria has defied every international attempt to bring peace, and there was no sign that the plan Annan described Tuesday will be a breakthrough. Although the Assad government's crackdown has turned the Syrian president into an international pariah, he still has the support of strong allies such as Russia, Iran and China.

There is little support for military intervention of the type that helped bring down Libya's Moammar Gadhafi, and several rounds of sanctions and other attempts to isolate Assad have done little to stop the bloodshed.

Still, Annan's latest efforts to reach out to Syrian allies suggest he sees them as integral to solving the crisis.

Annan was scheduled to brief a closed meeting of the UN Security Council by videoconference from Geneva on Wednesday on his meeting with Assad and visits to Iran and Iraq.

The council must decide in the coming days whether to extend the mandate of the UN observer force in Syria, which expires on July 20.

In New York, a UN diplomat, speaking on condition of anonymity because he was not authorized to speak publicly, said that Russia has circulated a draft resolution to the UN. Security Council that would extend the UN observer force in Syria but refocus its activities on trying to achieve a political solution to the conflict.

Since Assad took power following the death of his father, Hafez, in 2000, he has deepened cultural, political and economic ties with Iran, making it Syria's strongest regional ally. Tehran, in turn, has boosted Assad's military, providing it with advanced communications technology and weapons.

'My presence here proves that I believe Iran can play a positive role and should therefore be a part of the solution in the Syrian crisis.'—UN special envoy to the Syrian crisis Kofi Annan

All of this makes Iran unlikely to support change in Syria.

On Tuesday, Annan said Tehran has offered its support to end the conflict and must be "part of the solution."

"My presence here proves that I believe Iran can play a positive role and should therefore be a part of the solution in the Syrian crisis," Annan told reporters in Tehran after meeting with Iranian Foreign Minister Ali Akbar Salehi.

Annan said he has "received encouragement and co-operation" from the Iranian government but did not elaborate. Salehi also did not spell out what Tehran was willing to do to help tame the violence.

Annan's gestures to Iran in particular appear to oppose the approach of Washington, which has rejected Iran's participation in helping solve the crisis.

Sectarian tensions

The conflict in Syria is complicated by sectarian tensions.

Sunnis make up most of Syria's 22 million people, as well as the backbone of the opposition. But Assad and the ruling elite belong to the tiny Alawite sect, an offshoot of Shiite Islam.

Iraq's prime minister is a Shia, and Iran is a Shia powerhouse in the region.

The six-point peace plan Annan brokered earlier this year has failed to gain traction on the ground in Syria.

Government forces and rebels have widely disregarded a cease-fire that was to begin in April, and spreading violence has kept nearly 300 UN observers monitoring the truce stuck in their hotels in Syria.

Annan stressed the urgency of finding a solution to the crisis.

"If we don't make a real effort to resolve this issue peacefully and it were to get out of hand and spread in the region, it can lead to consequences that none of us could imagine," he said.