Given his tenuous hold on power, that makes Assad more likely to employ chemical or biological weapons in the 2-year-long fight against rebel forces seeking his ouster, said James Clapper, the director of national intelligence in testimony before the Senate Intelligence Committee Tuesday.
He said Assad is known to possess chemical weapons and a biological weapons program "may have advanced beyond the research and development stage." He also said the chemical or conventional weapons already possessed could be modified to deliver the biological weapons, should Assad choose to use them.
Clapper and other top intelligence officials testified to their annual assessment of global threats.
Clapper estimated with "low confidence" North Korea would only use a nuclear weapon if the Kim dictatorship was threatened. He said analysts still don't know what would prompt the reclusive state to deploy one of the nuclear weapons it has developed.
"We do not know Pyongyang's nuclear doctrine or employment concepts," Clapper said. "Although we assess with low confidence that the North would only attempt to use nuclear weapons against U.S. forces or allies to preserve the Kim regime, we do not know what would constitute, from the North's perspective, crossing that threshold."
Notable deaths of 2014 [PHOTOS]