Pentagon chief warns Syria against using chemical weapons

US Defence Secretary Jim Mattis said in Israel on Friday that there can be "no doubt" Syria has retained some chemical weapons and warned President Bashar al-Assad's regime not to use them.Mattis made his comments during a one-day visit for talks with Israeli leaders, who strongly backed a recent US strike against a Syrian airbase in retaliation for an alleged chemical attack on a rebel-held town."The bottom line is there can be no doubt in the international community's mind that Syria has retai