The arming of Syria's rebels will have "very bad implications in the region," Iran's Defence Minister Ahmad Vahidi said on Saturday, according to state television.
He added that "the region will face a major crisis if foreign forces, currently (covertly) present in Syria, enter the scene" and intervene militarily.
"The losers of such a crisis will be the Westerners and pro-Zionist countries," he predicted.
Iran has accused Saudi Arabia, Qatar and Turkey of arming the opposition in Syria, in collusion with the United States and Israel, to overthrow the regime of Tehran's key ally, Syrian President Bashar al-Assad.
Signup to our newsletter and follow us on Facebook and Twitter!
"The enemy seeks to create a new balance of power between the Zionist regime (Israel) and other Islamic countries in the region by forcing Syria out of the (anti-Israeli) resistance front. However, this will not come about."
UN Secretary General Ban Ki-moon said on Friday that the Syrian conflict has become a "proxy war, with regional and international players arming one side or the other."
Tehran denies it has sent any troops to aid Assad's regime.
"Iran has no armed forces in Syria and the Syrian government has not made such a request," Vahidi said, according to report on the website of state television channel IRIB.
"Syria has a powerful military and also enjoys popular support. The Syrians can handle the adventures that foreigners have created in their country."