Nikki Haley told an emergency meeting of the UN Security Council called by Russian Federation that should the U.S. and its allies decide to act in Syria it will be to defend "a bedrock worldwide norm that benefits all nations" - the prohibition on the use of chemical weapons.
Trump made clear in his eight-minute television address that he is wary of a deeper entanglement in Syria, where about 2,000 USA troops have been deployed to fight Islamic State.
But the pinpoint strike did not deter Assad and U.S. officials, speaking on condition of anonymity, have since investigated as many as 10 suspected chemical attacks.
The statement also warned about attacks on routers, the devices that channel data around a network.
The Secretary-General of the United Nations Antonio Guterres said at the session that the worsening situation in the Middle East is threatening global peace and security.
Ali Akbar Velayati, the top adviser to Iranian Supreme Leader Ayatollah Ali Khamenei, said during a visit to Damascus on Tuesday that an Israeli attack on an air base in Syria earlier this week would "not remain without response".
Over the weekend, the Pentagon said Russian "trolling" activity increased 2,000 percent in the wake of the Syria strike - but neither country identified any of the specific targets of the attacks.
"God forbid anything adventurous will be done in Syria on the lines of the Libyan and Iraqi experience", he told a news conference, referring to Western interventions elsewhere in the region.
We warned that such actions will not be left without consequences. The answer was: it's a secret; we can not provide this data.
Speaking from the White House late Friday, US President Donald Trump said the three nations had "marshalled their righteous power against barbarism and brutality".
Russia's ambassador to the United Nations, Vassily Nebenzia, told reporters "The situation (in Syria) is very risky".
"The immediate priority is to avert the danger of war", said Ambassador Vassily Nebenzia. "We hope there will be no point of no return".
He noted that the Russian and USA militaries have a hotline to prevent incidents, adding that it's not clear if it would be sufficient amid mounting tensions. The statement said none of the patients had any symptoms of chemical poisoning.
Trump cancelled a planned trip to Latin America on 13 April to focus instead on talks with Western allies about possible military action to punish Assad. It is claimed they were from the Wagner Group, a private army Moscow is said to be using in Syria. "If Russia had lived up to its commitment, there would be no chemical weapons in Syria, and we would not be here today".
Russia, which has stonewalled diplomatic efforts at the UN Security Council, has vehemently denied a chemical attack took place and accused the West of seeking an excuse for military action. "Could be very soon or not so soon at all!"
Ciaran Martin, chief executive of the UK's National Cyber Security Centre, said his country have been tracking the activity for close to a year and can independently verify the campaign and its attribution to the Russian government. This time with our allies, we have struck harder. The government's capture of Douma, the last town held by the rebels in Eastern Ghouta, marked a major victory for Mr Al Assad. Russian Federation is Assad's most powerful ally and its devastating air power has helped him wrest back large areas of territory from rebels since 2015.