UNITED NATIONS - UN leaders have "agonized" over a report that Secretary General Ban Ki-moon will present Monday on chemical weapons in Syria that could renew pressure on President Bashar al-Assad, officials said.
Ban has already revealed that he expects the report by a UN investigation team to the UN Security Council to give "overwhelming" confirmation that arms were used in an attack near Damascus on August 21 in which hundreds died.
But the UN team is not allowed to say who carried out the attack, which the West blames on Assad. While diplomats say the detail will give a clear pointer to who is responsible, opponents and supporters of Assad - who pleads innocence - will be looking for evidence to back their case.
A Russia-US accord on the dismantling of Syria's chemical stockpile will also weigh heavily on Security Council consultations expected to be called Monday.
Russia's Foreign Minister Sergei Lavrov on Saturday slammed what he called attempts to "retouch" the UN report. Syria's UN envoy, Bashar Jaafari, has also said his government will not accept a "politicised" report.
"Russia, the Americans, all sides, have been putting on pressure over this report," a UN official told AFP, speaking on condition of anonymity. "Ban's office has agonized over every word. The message has to be how serious this attack was but also support the Russia-US initiative."
Diplomats from various countries also confirmed approaches to Ban about the report.
The UN team, led by Swedish expert Ake Sellstrom, went to Damascus on August 18 to investigate claims that chemical weapons were used near Aleppo on March 19 and at two other sites, which have been kept secret.
They were in Damascus when the attack on opposition-held Ghouta in the suburbs was staged on August 21. The United States says 1,400 people were killed, and, backed by Britain and France, has blamed the Assad government. The team was immediately put onto the Ghouta attack and will return later to investigate the other sites.