Iran lambasted the Arab League for allowing an opposition leader to fill Syria's vacant seat at the organization's annual summit and described it as "dangerous behavior," Iranian media reported late on Tuesday.

With Syrian membership to the Arab League suspended in November 2011, the seat at Tuesday's summit was filled by Moaz Alkhatib, the leading figure among Syria's opposition coalition that is battling to overthrow President Bashar Assad.

Russia also criticized the Arab League for giving a seat formerly held by the Syrian government to a representative of the Syrian opposition.

"In Doha, another anti-Syria step was taken: a delegation of the Syrian National Coalition was invited and given the right to take the seat of official representatives of Syria in the meeting room," the Russian Foreign Ministry said in a statement.

Shi'ite Iran has given crucial backing to Assad since the protests erupted in Syria in 2011. Tehran regards him as key in the axis of resistance against Israel and a bulwark against what it says are extremist Sunni groups operating in Syria.
"Assigning Syria's seat to the Arab League to those who don't have the backing of the people establishes a pattern of dangerous behavior for the Arab world that can set a new precedent for other members of the Arab League in the future," said deputy foreign minister, Hossein Amir Abdullahian, Iran's student news agency (ISNA) reported.

"These actions will bring an end to the organization's role in the region," he said.

At the summit, Moaz Alkhatib asked U.S. Secretary of State John Kerry for American forces to help defend rebel-controlled northern parts of Syria with Patriot surface-to-air missiles based in Turkey. NATO swiftly rebuffed the idea.

The summit also endorsed the provision of military aid to Syrian rebels. A communiqué affirmed member states had a right to offer assistance "including military, to support the steadfastness of the Syrian people and the Free Army."

Iran has proposed a six-point plan for Syria and emphasized the importance of elections and reforms, but does not accept the removal of Assad, saying a solution to the crisis cannot be imposed from outside the country.