NEW : Syrian minister denies government forces used chemical weapons . The UN has said it is investigating the alleged use of sarin gas by President Bashar Assad's regime against its own people. The opposition says that Syrian forces used the nerve gas sarin as a weapon . UK prime minister talks with Canadian leader , U.S. president about `` all the options ''
NEW : Syrian minister denies government forces used chemical weapons . Some 1,300 were reported killed in the early Wednesday attack in Damascus ' outskirts . The opposition says that Syrian forces used the nerve gas sarin as a weapon . UK prime minister talks with Canadian leader , U.S. president about `` all the options ''