At an emergency U.N. Security Council meeting called by Russian Federation, the three powers dismissed Moscow's accusations that they had violated global law and the provisions of the U.N. Charter.
Moving to return to diplomacy, France said it was working with the United States and Britain on a draft resolution that would address chemical weapons use, the humanitarian crisis and the future of the peace process in Syria.
She told reporters ahead of the meeting that London "believes it was both right and legal" to take military action "to alleviate further humanitarian suffering by degrading the Syrian regime's chemical weapon capability and deterring the use of chemical weapons".
The joint operation by the USA and its allies was in response to a suspected chemical attack in the city of Douma last week.
"I reiterate my strong condemnation of the use of chemical weapons by any party to the conflict and under any circumstances".
Air strikes by the allies on Saturday hit three targets that Western officials said were linked to chemical weapons development in the Damascus and Homs areas.
The OPCW mission should be granted full access, without any restrictions or impediments to perform its activities, he said. A second is expected to arrive on Friday or Saturday.
I have repeatedly expressed my deep disappointment that the Security Council failed to agree on a dedicated mechanism for effective accountability for the use of chemical weapons in Syria.
The three allies have not given up on a political solution to the Syrian conflict. "The solution must be political through the Geneva intra-Syrian talks".
"The Cold War is back - with a vengeance but with a difference", Gutteres warned.
And in what appears to be implicit criticism of Israel for its use of force against protesters, Guterres said, "The recent violence in Gaza has resulted in many needless deaths and injuries".
Mechanisms and precautionary measures to contain the risks of escalation had already left.
In Syria, Guterres said, "we see confrontations and proxy wars involving several national armies, a number of armed opposition groups, many national and worldwide militia, foreign fighters from everywhere in the world, and various terrorist organizations".
Guterres cited the Palestinian-Israeli divide, the Sunni-Shiite divide "evident from the Gulf to the Mediterranean", opposing attitudes on the Muslim Brotherhood and the status of the Kurds, threats to communities that have lived in the region for millennia, and other factors.