Iran has warned that foreign military intervention in Syria will result in a conflict that would engulf the region.
The threatening rhetoric from Tehran came in response to a statement by the secretary of state, John Kerry, on Monday that the US would respond to the "undeniable" use of chemical weapons in Syria.
In the strongest signal yet that the US intends to take military action against the Assad regime, Kerry said President Bashar al-Assad's forces had committed a "moral obscenity" against his own people.
"Make no mistake," Kerry said. "President Obama believes there must be accountability for those who would use the world's most heinous weapon against the world's most vulnerable people. Nothing today is more serious, and nothing is receiving more serious scrutiny".
Iranian foreign ministry spokesman, Abbas Araqchi, indicated it was equally resolved to defend Assad.
"We want to strongly warn against any military attack in Syria.
There will definitely be perilous consequences for the region," Araqchi told a news conference. "These complications and consequences will not be restricted to Syria. It will engulf the whole region."
Shi'ite Iran is Syria's closest ally and has accused an alliance of militant Sunni Islamists, Israel and western powers of trying to use the conflict to take over the region. (+ video) » | Paul Lewis in Washington, Martin Chulov in Beirut, Julian Borger and Nicholas Watt | Tuesday, August 27, 2013