U.S President Obama warns Syrians of chemical weapon uses U.S President Barack Obama says, the use of chemical weapons by Syria will be a red line that will change his thinking on intervention in the crisis. He said, he had at this point not ordered military engagement but indicated that there will be enormous consequences if the use of chemical weapons is encouraged. Earlier, the new UN Special Envoy to Syria, Mr. Brahimi, faced criticism for refusing to say whether President Bashar al-Assad must quit. Speaking to reporters at a White House briefing, President Obama said, the deployment or use of biological weapons will widen the conflict in the region. He warned President al-Assad and other players on the ground about the use or movement of such weapons. Meanwhile, fighting continued in several Syrian cities yesterday, including Damascus, Deraa and Aleppo. A Japanese veteran war reporter working for Japan press, Mika Yamamoto, was killed by gunfire in Aleppo. The UN says more than 18 thousand people have been killed in the conflict while 170 thousand have fled. BBC