"The final report is expected to be finalized in early December, after all information gathered by the UN Mission has been evaluated," Nesirky said at a daily briefing here.
"A number of samples are still being analyzed by the designated laboratories and the results are expected to be provided to the UN Mission early next week," he said.
On Sept. 16, Ake Sellstrom, head of the UN team to investigate the alleged use of chemical weapons in the Syrian conflict, presented an initial report to UN Secretary-General Ban Ki-moon, confirming that sarin gas was used outside the Syrian capital of Damascus on Aug. 21.
The UN team is mandated to find out whether chemical weapons were used in the Arab country, but not who used them.
"Prof. Sellstrom is currently working on the final report in coordination with the Organization for the Prohibition of Chemical Weapons and World Health Organization experts that were part of the UN Mission," Nesirky said.
Samples collected by the UN team in Syria were transferred from The Hague to laboratories for analysis on Sept. 2. They were gathered from the site of the alleged use of chemical weapons in the Ghouta area of Damascus, which allegedly killed more than 1, 000 people.
The UN said the analyses would be conducted in laboratories in Europe "strictly adhering to the highest established standards of verification recognized by the Organization for the Prohibition of Chemical Weapons."
The fact-finding group, which was created in March at the request of the Syrian government, was initially set to investigate the alleged March 19 chemical attacks on Khan al-Asal in the northern province of Aleppo and two other undisclosed sites. The mission was later ordered to investigate the Ghouta case.
The investigators arrived in Syria on Aug. 18 and left the war- torn country on Aug. 31.
Xinhuanet