Syria's two distinct chemical weapons inspections
There are two distinct chemical weapons missions to Syria, a United Nations mission to probe alleged attacks and an Organisation for the Prohibition of Chemical Weapons (OPCW) mission to destroy stockpiles.
The UN inspectors leave Damascus on Monday, while OPCW inspectors arrive on Tuesday.
Although the teams may cross paths, and UN inspectors may eventually join the OPCW disarmament mission, no inspectors will simply swap missions next week.
The UN mission
UN experts sent by Secretary General Ban Ki-moon are investigating seven alleged chemical weapons attacks, but are not expected directly to pin the incidents on any particular party to the Syrian conflict.
Led by Swedish chemical weapons expert Ake Sellstrom, the mission has drawn on the expertise of OPCW inspectors and the use of its lab facilities to analyse Syrian samples.
The UN inspectors returned to Damascus this week and are expected to wrap up their work on Monday, with a comprehensive report ready by late October.
The team is continuing its investigations into the massive August 21 attack in the Ghouta area in the suburbs of Damascus, which occurred during their group's first mission to Syria last month.
Western outrage at that attack, in which the US says more than 1,400 people died, led to the threat of US-led military action against Syria.
A subsequent US-Russia deal under which Syria agreed to dispose of all its chemical weapons saw the threat of military action averted.
As part of the deal, Syria agreed to join the Chemical Weapons Convention (CWC), which is enforced by the Hague-based Organisation for the Prohibition of Chemical Weapons (OPCW).
The OPCW mission
As the body that enforces the CWC, the OPCW is charged with planning and executing the eradication of Syria's chemical weapons.
Its inspectors are to start work in Syria on Tuesday, once the OPCW's Executive Council adopts the US-Russia roadmap to avert military strikes on Syria.
That roadmap, which sees all Syrian chemical weapons destroyed by mid-2014, will in turn go into a UN Security Council resolution to enforce Syria's chemical disarmament.
OPCW inspectors will not only be able to visit weapon and stockpile locations declared by Damascus as part of the Russia-US deal, but also any other suspected chemical weapons sites.
All Syrian chemical weapons facilities must be inspected no later than 30 days after the document is adopted by the Executive Council.
The OPCW Executive Council is to decide on "intermediate destruction milestones" by November 15, it says, calling also on Syria to provide "immediate and unfettered right to inspect any and all sites".
© 2013 AFP