A senior Iranian official says his country would consider any attack on Syria an attack on itself.
The semiofficial Mehr news agency quoted Ali Akbar Velayati, an adviser to Supreme Leader Ayatollah Ali Khamenei, as saying on January 26 that the Syrian regime played a "key role in the region for promoting firm policies of resistance."
Tehran sees Damascus as part of an axis of opposition to Israeli and Western influence in the Middle East.
It has kept up its strong support for Syrian President Bashar al-Assad since a revolt against his rule erupted in March 2011.
Meanwhile, NATO says the first of six Patriot missile-defense batteries deployed to Turkey along the border with Syria has been declared operational.
The United States, Germany, and the Netherlands are providing two batteries each of the U.S.-made Patriots.
NATO said on January 26 that the first battery to become operational was a Dutch unit that will help protect the city of Adana.
The rest of the batteries are expected to become fully operational by the end of the month.
Alliance member Turkey asked NATO in November to deploy the Patriot missiles to beef up its air defenses amid fears about a spillover of the Syria conflict.
The Syrian government has described the NATO deployment as a provocation.
Based on reporting by Reuters and AP