"I hope that this behavior by Syria, in what clearly is cooperation with Russian Federation and Syria together, will never happen again, " he said.
Team Trump, meanwhile, was still basking in the praise he received from many quarters for the retaliatory attack on the Syrian air base from which the planes carrying chemical weapons were launched.
The regime of Russian President Vladimir Putin is closely allied with that of Assad.
UN Ambassador Nikki Haley said that new actions could be taken against Syria. "But I think he will have to look at the situation", Nikki Haley told CNN on Sunday when asked whether Trump "wants tougher sanctions on Russian Federation and Iran".
Asked about reports that Syria's government began conducting bombings using the same base struck by the US on Thursday, McMaster pushed back.
He said: "Using a deadly nerve agent, Assad choked out the lives of helpless men, women and children".
"In no way do we see peace in that area with Assad as the head of the Syrian government", Haley told NBC's "Meet the Press".
"I acted in the vital national security and foreign policy interest of the United States", Trump said in a letter to both chambers of the Congress dated Saturday.
Pressed by Fox host Chris Wallace to explain Tillerson's statements that destroying ISIS was the priority for the US, McMaster responded: "That's exactly what we're saying". "Why are we supporting this murderous regime that is committing mass murder of its own population?"
The frigate Admiral Grigorovich, which had taken part in Russian operations in Syria the year before, took about three hours to pass through the strait and reach the Aegean Sea.
"The failure related to the recent strike and the recent awful chemical weapons attack in large measure is a failure on Russia's part to achieve its commitment to the worldwide community", Tillerson said in an interview aired on ABC on Sunday. "The first priority for them was to cover for Assad".
They said the countries will not be deterred from "liberating" Syria.
"They helped broker the original deal to put chemical weapons out of commission".
Tillerson stopped short of accusing Russian Federation of direct involvement in planning or carrying out the attack, saying he had not seen "any hard evidence" to suggest Moscow was an accomplice to Assad. He did not specify the action.
Most U.S. allies have rallied around Washington in the aftermath of the suspected chemical-weapons attack and subsequent U.S. missile strike.
Haley noted that the United States' first priority is still to defeat ISIS, but that there can be "multiple priorities".
"We can not let this happen again", Tillerson told reporters as he prepared to go to Moscow, where he is to deliver an ultimatum.