A delegation of experts from the Organisation for the Prohibition of Chemical Weapons, based in The Hague, is tasked with investigating an April 7 attack on Douma, just east of Damascus.
The team had been expected to begin their field work on Sunday but they met with officials at their Damascus hotel instead and a strict media blackout was imposed on their schedule.
Russian Federation backs Syrian President Bashar al-Assad's government.
US, French and British missiles destroyed sites suspected of hosting chemical weapons development and storage facilities, but the buildings were mostly empty and the Western trio swiftly reverted to its diplomatic efforts.
As the on-the-ground investigation fails to get under way, the fallout from the US-led response continues to reverberate, with French President Emmanuel Macron claiming to have persuaded President Donald Trump to keep his troops in Syria.
Trump's "Mission Accomplished" tweet earned him parallels with George W. Bush's fatefully premature victory speech days after the 2003 invasion of Iraq.
The US-led strikes were the biggest global attack on President Bashar al-Assad's regime since the start of Syria's seven-year war.
The world's chemical weapons watchdog is set to convene Monday to discuss the suspected toxic gas assault in Syria that prompted an unprecedented wave of Western strikes, as its inspectors probe the attack near Damascus.
Yet the Pentagon has said it planned no further strikes and the West already appeared to be shifting its focus to renewed diplomatic action, with a new resolution to be debated at the UN Security Council on Monday.
"In my opinion, it was a staged drama, orchestrated by Trump and Putin, for each to save face", he said. Too many duck the responsibility that comes with being a member of this council.
The OPCW arrived in Syria a day before the joint punitive airstrikes from the United States, Britain and France a week after the alleged chemical attack in Douma, where activists say more than 40 people were killed.
He told BBC One's The Andrew Marr Show: "There is no proposal on the table at the moment for further attacks because so far - thank heavens - the Assad regime has not been so foolish to launch another chemical weapons attack".
Regime forces have since entered Douma and declared the entire Eastern Ghouta region around it fully retaken, ending a five-year siege and reclaiming an opposition bastion on the edge of the capital.
Over the weekend the OPCW sent inspectors on a fact-finding visit to Douma to search for evidence and interview witnesses.
"We will ensure they can work professionally, objectively, impartially and free of any pressure", he said, adding he was confident the experts would prove chemical weapons were never used.
Syrian Deputy Foreign Minister Faisal Mikdad met overnight with representatives of the worldwide chemical weapons watchdog at a Damascus hotel.
The US President has declared the US, UK and French strikes on Syria a success, as Russian Federation has described them unlawful.
With all key players having de facto preempted its findings, the chemical arm watchdog faced a hard task. He also said the team could not access the site without an appropriate United Nations permit.