President Barack Obama says the use or movement of chemical weapons by Syrian President Basher al-Assad’s regime would change the U.S. perspective on how to respond to the crisis.
Speaking at a White House news conference on August 20, Obama said he had not ordered U.S. military intervention in Syria "at this point."
But he warned Assad and "other players on the ground" that the use or movement of chemical weapons would be a "red line" that would change his thinking on intervention in the crisis.
"There would be enormous consequences if we start seeing movement on the chemical weapons front or the use of chemical weapons," the U.S. president said.
Syria last month acknowledged for the first time that it had chemical and biological weapons and said it could use them in case of any "external aggression."
Assad's military regime is believed to have mustard gas as well as nerve agents such as tabun and sarin that can be delivered in missiles, bombs, rockets, and artillery shells.
Obama said the deployment or use of such weapons would widen the conflict in the region.
"That's an issue that doesn't just concern Syria, Obama said. It concerns our close allies in the region, including Israel. It concerns us. We cannot have a situation where chemical or biological weapons are falling into the hands of the wrong people."
Western countries and Israel have expressed fears Syrian chemical and biological weapons could fall into the hands of militant groups.
Israel has said that if Syrian-backed Hizballah guerrillas used the situation to take control of the weapons, it would "act immediately and with utmost force."
Meanwhile, reports from Syria say deadly fighting continued on August 20 in several parts of the country, including the northern city of Aleppo, the southern city of Daraa, and in several neighborhoods of the capital, Damascus.
Japan's Foreign Ministry confirmed that a female Japanese reporter, Mika Yamamoto, died after being “caught in gunfire” in Aleppo.
The Syrian Observatory for Human Rights reported that three other foreign reporters had disappeared in Syria's second-largest city.
The Britain-based group said the three included two Arabs -- one a Lebanese woman -- and a Turkish reporter.
The United Nations estimates that more than 18,000 people have been killed in a conflict that has already dragged on for a year-and-a-half, 170,000 have fled Syria, and 2.5 million need aid inside the country.
Based on reporting by Reuters, AFP, and AP