The US is concerned over the possible acquisition of Syria's undeclared chemical weapons-if any- by the most dangerous terrorist groups, United Nations Ambassador Samantha Power said.
According to the Huffington Post, Power spoke to reporters after the Security Council received a briefing from Sigrid Kaag, who heads the international effort to rid Syria of its chemical weapons.
The UN and the Organization for the prohibition of Chemical Weapons' joint mission to destroy all of Syria's declared stockpile will be over by the end of the month.
However, Kang said the OPCW was still in talks with Syria over undisclosed chemical weapons.
Power said that if Syrian President Bashar Assad was hiding any stockpiles, chances were high that it could fall into the hands of extremist groups who have "committed some of the most vile acts in the last few days".