WASHINGTON, Dec. 3 (Xinhua) -- U.S. President Barack Obama on Monday warned Syrian President Bashar al-Assad of "consequences" in using chemical weapons in the Arab country's 21-month conflict.
Addressing at the National Defense University in Washington, D. C., the U.S. president repeated a warning echoed hours earlier by his top diplomat, Secretary of State Hillary Clinton, in Prague, the Czech Republic.
"Today, I want to make it absolutely clear to al-Assad and those under his command, the world is watching," Obama said at an event on securing nuclear weapons materials in former Soviet Union region.
"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," he said.
"We simply cannot allow the 21st century to be darkened by the worst weapons of the 20th century," Obama declared, vowing to continue efforts to make a transition in Syria.
He did not elaborate on what exactly the consequences were.
Earlier in the day, his press secretary Jay Carney said “Contingency planning of all kinds is a responsible thing to do."
Press reports quoted U.S. officials as saying that intelligence had detected movement of chemical weapons in Syria in recent days, prompting Clinton to reiterate U.S. "red line" on the issue in Prague.
"This is a red line for the United States," she said. "I am not going to telegraph in any specifics what we would do in the event of credible evidence that the Assad administration has resorted to using chemical weapons against their own people. But suffice it to say we are certainly planning to take action if that eventuality were to occur."