DUBAI, United Arab Emirates — Iranian Supreme Leader Ayatollah Ali Khamenei said on Wednesday U.S. intervention in Syria would be "a disaster for the region," the ISNA state news agency reported, as Western powers made plans to hit Damascus over a chemical weapons attack.

After supporting Arab uprisings across the Middle East and north Africa in 2011 as examples of what Khamenei called an Islamic awakening, Tehran has steadfastly supported the secular President Bashar al-Assad, its main strategic ally in the Middle East, against a two-and-a-half-year-long rebellion.

"The intervention of America will be a disaster for the region. The region is like a gunpowder store and the future cannot be predicted," the agency quoted Khamenei as saying.

Iran is concerned that if Assad were overthrown, he would be replaced by either allies of the West or by radical Sunni Muslims tied to Saudi Arabia, both seen as hostile by the Shiite Muslim Iranians. Syria is also a conduit for Iranian supplies to Shiite Hezbollah militants in Lebanon.

Iranian officials have condemned the use of chemical weapons — deployed against its troops during the 1980-88 Iran-Iraq war — but have blamed Syrian rebels for the Aug. 21 poison gas attack that killed hundreds in the embattled suburbs of Damascus.

"As a victim of chemical weapons the Islamic Republic of Iran does not tolerate the use of such weapons. In addition, it also does not tolerate a group of countries giving themselves the permission to wage a campaign in the region," Foreign Minister Mohammad Javad Zarif told state television.

"This fire of sectarianism, tribal conflicts, and conflicts that . . . are exacerbated for short-term interests cannot be restricted to one region. "If [Obama] gets stuck in this trap, he will certainly leave behind bad memories of his presidency," he said.