The United Nations disarmament chief arrived in the Syrian capital on Saturday to press Bashar Assad's regime to allow U.N. experts to investigate an alleged chemical weapons attack this week that reportedly killed more than 1,300 people, AP reported. Angela Kane, who was dispatched by the U.N. secretary-general to push for a speedy investigation into Wednesday's purported attack outside the Syrian capital, did not speak to reporters upon her arrival in Damascus. The U.S., Britain, France and Russia have all urged the Assad regime and the opposition fighters fighting him to cooperate with the United Nations and allow U.N. experts already in Syria to look into the latest purported use of chemical agents. Anti-government activists accuse the Syrian government of carrying out a toxic gas attack on the eastern suburbs of Damascus on Wednesday and have reported death tolls ranging from 136 to 1,300. The Assad regime has denied the claims that it was behind the chemical attack.