RENO: US President Barack Obama warned Syrian strongman Bashar al-Assad on Monday not to make the "tragic mistake" of deciding to unleash his stockpile of chemical weapons.
Assad's beleaguered regime had earlier threatened to use such weapons if Syria faced international military intervention, although it vowed not to turn them against its own civilians.
"Given the regime's stockpile of chemical weapons, we will continue to make it clear to Assad and those around him that the world is watching," Obama told an audience of US veterans in the western state of Nevada.
"They will be held accountable by the international community and the United States should they make the tragic mistake of using those weapons," he said.
Earlier, Syrian foreign ministry spokesman Jihad Makdissi had warned Syria could use chemical weapons if attacked by outsiders, although he back-tracked later to clarify that he was not confirming Damascus has such arms.
"Syria will not use any chemical or other unconventional weapons against its civilians, and will only use them in case of external aggression," he said.
Syria is in the grip of a 16-month-long conflict triggered by Assad's brutal repression of a pro-democracy revolt. Western and Arab powers have called for him to step down and allow an orderly transition of power.
US officials also demanded that the Assad regime act responsibly and safeguard any such unconventional arms.
Denouncing Makdissi's words as "horrific and chilling," State Department spokeswoman Victoria Nuland said "that any possible use of these kinds of weapons would be completely unacceptable."
"The Syrian regime has a responsibility to the world, has a responsibility first and foremost to its own citizens to protect and safeguard those weapons," she insisted to reporters.
"That kind of loose talk just speaks to the kind of regime that we're talking about."
Pentagon press secretary George Little also warned Syria: "They should not think one iota about using chemical weapons."
Nuland said Washington was working with its allies to monitor the situation but refused to detail what kind of chemical weapons the Syrians might have in their arsenal, saying she could not discuss intelligence matters.
Israel has also stepped up the rhetoric against Syria, warning it could take military action if any of its advanced weapons end up in the hands of Hezbollah.
Nuland said the issue of Syria's chemical weapons was among topics discussed earlier in July during US Secretary of State Hillary Clinton's trip to Israel.
"Like all countries in the neighborhood, it makes sense for there to be prudent planning for self-defense," she said when asked about Israel's threat of military action. (AFP)