Iran on Monday threw its weight behind a plan outlined by Syrian President Bashar al-Assad to end the civil war in his country, reiterating Tehran's solid support for its most important regional ally.

"The Islamic republic... supports President Bashar al-Assad's initiative for a comprehensive solution to the country's crisis," Iranian Foreign Minister Ali Akbar Salehi said in a statement on his ministry website.

"Assad's plan includes solutions which reject violence and terrorism and any foreign interference in the country, and outlines a comprehensive political process" to end the conflict, Salehi said.

Pre-dominantly Shiite Iran has given economic aid and military advice to Syria, whose secular ruling regime counts many figures from the minority Alawite branch of Shia Islam. Tehran sees Assad's Syria as a bulwark against Israel.

Assad, in a rare speech on Sunday, offered a proposal to resolve the conflict in Syria that called for an end to violence, dialogue with opposition elements he deemed acceptable, and a vow to stand fast against those he branded "terrorists" and their foreign backers.

The Syrian opposition and the West, though, immediately rejected the initiative as a defiant restating of Assad's intent to cling to power.

The 21-month conflict that wracking Syria has claimed more than 60,000 lives acoording to the United Nations.