The foreign-backed armed groups that had surrounded the base close to Damascus are "the more extreme kind," said the head of the mission responsible for disposing Syria's chemical weapons arsenal, Sigrid Kaag, as quoted in a Frida report by the Associated Press.
Global extremism has come to Syria, Kaag warned.
It is not possible at the moment to arrange a cease-fire and get to the large military airfield by road, she added.
It would take "less than a working week" to pack the most dangerous chemicals into five containers and the less toxic chemicals into 11 containers, put them on a convoy and get them to the port of Latakia, she said.
Danish and Norwegian ships are waiting in the port city to take the containers to a US vessel for destruction.
Earlier this week anti-Damascus opposition elements reportedly announced that the militants surrounding the base near Damascus are from the so-called 'Islamic Front,' which is one of the largest and most heinous insurgent coalitions in Syria.
Syria has been removing 1,300 metric tons of chemical weapons under a deal reached last year, which averted US-led military strikes in the country, after a sarin gas attack on insurgent-held suburbs around the Syrian capital in August.
Syria has missed several deadlines to ship out the toxins - the last of which was April 27 - because the site referred to by Kaag is difficult to reach due to terrorist attacks.
NTJ/MB