UN inspectors yesterday returned to Syria to pursue a probe into alleged poison gas attacks, as Russia and the West wrangled over how to eliminate President Bashar al-Assad's banned chemical weapons.
The group, led by chief expert Ake Sellstrom, flew to Beirut in Lebanon and travelled by overland convoy via the Masnaa border post to Damascus.
In another complication, 13 key Syrian Islamist groups said they did not recognise any foreign-based opposition group, including the main Turkey-based Syrian National Coalition.
The groups include members of the main rebel Free Syrian Army and more radical Islamists such as Al-Nusra Front.
US President Barack Obama on Tuesday demanded tough Security Council action against Syria as the conflict there dominated debate at the annual UN General Assembly.
Sellstrom's team is expected to examine the alleged use of chemical weapons some 14 times in Syria's 30-month conflict that is estimated to have killed more than 110,000 people.
After a preliminary visit last month, the team concluded in a report presented on September 16 that banned chemical weapons had been used on a wide scale in the conflict between Assad's regime and rebel forces.
There was clear evidence that sarin gas was used in an attack in the Eastern Ghouta neighbourhood near Damascus on August 21, the report said.
Sellstrom pointed out that the report was only an interim document, and that other allegations needed to be looked into.
Sellstrom said the team hoped to be able to present a final report addressing all of the accusations "possibly by the end of October".
Last month's attack, which the Syrian opposition and some parts of the international community blame on the regime, prompted Washington to threaten military action against Damascus.
Assad's government denies using chemical weapons against its own people, and has agreed to a US-Russian plan that will see it hand over its chemical arsenal for destruction.
The deal headed off US military action, but Syrian regime ally Russia is still wrangling with Britain, France and the United States over the wording of a UN resolution enshrining the accord.
Obama told world leaders Washington was ready to "use all elements of our power, including military force" in the Middle East to defend "core interests" such as ensuring oil supplies and eradicating weapons of mass destruction.