If one does not conduct a military operation in Syria, several years may be required for political settlement of the crisis, U.S. Secretary of State John Kerry said on Monday, Al Arabiya TV channel reported.
Kerry also said that Iran has officially acknowledged the use of chemical weapons in Syria.
"The danger of inaction concerning the Syrian regime prevails over the danger of holding the operation against Damascus," he added.
Some Western countries as well as Turkey have already supported intervention in Syria following another escalation of the situation. On August 21, media outlets reported a large scale deployment of chemical weapons near Damascus by Syrian Government Troops. Over 600 people were victims of the attack.
Earlier, the U.S. president declared that the use of chemical weapon is a 'red line' for the Assad regime. Media outlets reported on preparations of the Navy and Air Force of these countries to begin intervention.
The clashes between the government forces and armed opposition have been continuing in Syria for over two years. According to UN statistics, the total number of victims of the conflict in Syria is more than 100,000. The Syrian authorities say they are opposed by well-armed militants.