There are still 12 facilities that hold chemical weapons in Syria, the special coordinator for the Joint Mission of the Organization for the Prohibition of Chemical Weapons and the United Nations, told the Security Council Thursday. The announcement raised fears that the Islamic State, also known as ISIS, could seize the weapons and use them against civilians.

“This is a chemical weapons disarmament process, it’s been unique,” Sigrid Kaag, head of the joint mission dealing with Syria's chemical weapons, said in her briefing to the Security Council. Kaag said that the team is in the process of preparing to destroy the remaining sites, but did not set a timeline.

Kaag told reporters that the team had destroyed 100 percent of "priority chemicals" and 96 percent of the entire stockpile. She did not specify which chemicals were "priority."

Despite the mission's work in destroying Syria's chemical weapons, the United Nations Human Rights Council reported last month that President Assad had used chlorine gas against civilians. 

The council endorsed the destruction of the rest of the regime's chemical weapon stockpiles in its meeting Thursday with a program that is set to begin with inspections Oct. 1.

Following the Security Council meeting, Ambassador Samantha Powers, in a Tweet, emphasized the importance of holding Assad accountable. 

The Security Council meeting Thursday comes during the middle of an international debate about how to deal with ISIS and its threat to the region. The U.S. and Britain both condemned the Sunni militant group after it released videos of the beheadings of U.S. journalists James Foley and Stephen Sotloff. 
Last week President Obama said he was working to create an international coalition to fight ISIS that would rely heavily on its Sunni allies in the region such as Saudi Arabia and the United Arab Emirates. The U.S. is already conducting targeted airstrikes in Iraq to stop the group from advancing toward Erbil, the capital of Iraqi Kurdistan. And on Tuesday, Obama approved the deployment of an additional 350 troops to the country, bringing the total to 1,100. The troops stationed in Iraq will serve no combat role, he said, but would work with the Iraqi and Kurdish military to strategize on how best to fight ISIS.