International envoy Kofi Annan said Tuesday that Iran must be "part of the solution" to the bloody crisis in its close ally Syria, and that the Tehran has offered its support to end the conflict.

Annan was in Iran in a bid to salvage his faltering peace plan for the 16-month-old crisis in Syria, which activists say has killed more than 17,000 people. The trip to Tehran comes a day after Annan agreed with Syrian President Bashar Assad on a new framework to stop the violence.

"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.

He said that he has "received encouragement and cooperation" from the Iranian government, he said but did not specify what support Tehran has offered.

A staunch ally of Syria, Iran has provided Assad with military and political backing for years, and has kept up its strong support for the regime since the Syrian uprising began in March 2011.

Annan did not say what kind of involvement he saw for Iran in resolving the crisis, nor did Salehi spell out what Iran was willing to do to help tame the violence.

Anti-regime fighters have dismissed any role for Iran in a plan they and some others say has little hope of succeeding. The United States, meanwhile, has rejected Iranian participation in international meetings on the Syrian crisis.

Annan brokered a six-point peace plan earlier this year, but it has struggled to gain traction on the ground.

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

After a two-hour meeting with Assad on Monday, Annan said the men had agreed on "an approach" to stop the violence, and that the diplomat would share it with the armed opposition.

He declined to provide more details on the new framework Tuesday in Tehran, saying only that "it relates to the efforts to end the violence.

"The details (have) to be worked out with the opposition. We have to discuss this with them. That's why I can't go into details but it relates to end the violence," he told reporters.

But the U.N. envoy 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.

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, as well as sending elite military advisers.

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

Salehi, Iran's foreign minister, said Tehran backs the rights of the Syrian people but opposes military intervention, and blamed the conflict's increasingly chaotic violence on the meddling of foreign powers.

"Unfortunately, the unwise interference of others has caused the situation in Syria to remain critical," he said. "The worsening of the situation should not happen. It would not benefit anyone in the region." (AP)