Ammon News - By AL ARABIYA WITH AGENCIES

A stark warning from U.S. President Barack Obama to Syrian President Bashar al-Assad late Monday followed new information revealed by a U.S. official that Syria may be on the verge of using chemical weapons.

Obama warned Assad not to use chemical weapons against Syrian opposition forces, saying there would be consequences if he were to do so.

“I want to make it absolutely clear to Assad and those under his command: The world is watching,” Obama said in a speech to a gathering of biological, chemical and nuclear weapons proliferation experts.

“The use of chemical weapons is and would be totally unacceptable and if you make the tragic mistake of using these weapons, there will be consequences and you will be held accountable,” Obama said.

Although the president did not give away how the United States might respond, White House spokesman Jay Carney said earlier that “contingency planning” was under way when asked whether the use of military force was an option, according to Reuters news agency.

The Damascus government, hitting back at increasingly explicit US rhetoric, had earlier pledged never to take such a step, which the Obama administration warns would cross a “red line” and result in US action.

Washington, along with supporting members of the international community, worries that battlefield advances by rebels could prompt Assad to use chemical arms, or that such stocks could become insecure or find their way into the hands of groups hostile to the United States and allies.

In televised remarks, an unnamed Syrian foreign ministry official said Syria would “never, under any circumstances, use chemical weapons against its own people, if such weapons exist.”

The New York Times reported that in addition to public warnings to Assad, U.S. and European officials had sent private warnings to Damascus through Russia.

A ‘game changer’
Secretary of State Hillary Clinton, during a trip to Prague, declined to “telegraph” what Washington would do if Syria used chemical weapons but said: “we’re certainly planning to take action if that eventuality were to occur.”

A 150-strong U.S. task force, including special forces soldiers, has been stationed in Jordan for several months, and could be called into action if Syria loses control of its chemical weapons amid battlefield chaos.

Jordanian Foreign Minister Nasser Judeh said in Washington that the use of chemical weapons in Syria would be a “game changer.”

“The regime knows that the international community will simply not accept for these weapons to be used in different scenarios: whether they are used by the regime against their own people or used against neighboring countries or fall into the wrong hands,” he said.

In Syria itself, there were new developments in a vicious conflict that has taken an estimated 41,000 lives since erupting in March 2011.