During his address, President Trump said U.S. forces were prepared to sustain this response "until the Syrian regime stops its use of prohibited chemical agents" and issued a direct message to Russian Federation and Iran which he said are "most responsible for supporting, equipping, and financing the criminal Assad regime".
Those comments raised immediate questions as to whether the military operation would extend beyond an initial round of missile strikes.
"The evil and the despicable attack left mothers and fathers, infants and children, thrashing in pain and gasping for air".
Iran's Supreme Leader Ayatollah Ali Khamenei said that the attack on Syria was a "crime" and declared the leaders of the U.S., France and the United Kingdom "criminals", according to Iran's state-run IRNA news agency.
"We specifically identified these targets to mitigate the risk of Russian forces being involved", Dunford told reporters, adding the USA military advised Russia of airspace that would be used in the strike but did not "pre-notify them".
France's foreign minister said the "chemical escalation" in Syria is not acceptable because it violated the rules of war and of humanity.
French defense minister Jean-Yves Le Drian on Saturday said Russian Federation was warned ahead of joint US, UK, French air strike on Syria. Military muscle-flexing would only complicate the situation in Syria, and is very likely to push further away any hope of a peaceful end to the long-running civil war by political means. He called on Moscow to change course and join the West in seeking a more responsible regime in Damascus.
In a statement Friday night, UK Prime Minister Theresa May called last weekend's chemical attack "pure horror".
Johnson said: "The world is united in its disgust for any use of chemical weapons, but especially against civilians". But soon there were new reports of chemical weapons attacks, with strong evidence implicating Syrian Government forces.
The one-off missile strike in April 2017 targeted the airfield from which the Syrian aircraft had launched their gas attack.
The Syrian government responded with defiance Saturday following President Trump's decision to take military action against chemical weapons production facilities in Syria, describing the attack as an "aggression" that would fail.
Nedher Hammoud, 48, claimed to have seen missiles "being shot down like flies".
Defense Secretary Jim Mattis said there were no reports of US losses in what he described as a heavy but carefully limited assault.
Trump chastised Syria's two main allies, Russia and Iran, for their roles in supporting "murderous dictators", and noted that Russian President Vladimir Putin had guaranteed a 2013 global agreement for Assad to get rid of all of his chemical weapons.
House Speaker Paul Ryan is praising Trump's "decisive action in coordination with our allies", adding, "We are united in our resolve". "Hopefully, someday we'll get along with Russian Federation, and maybe even Iran - but maybe not".
"We confined it to the chemical weapons-type targets", Mattis said.
Four UK Tornado jets targeted one of the sites - the facility to the west of Homs. Witnesses on the ground in Damascus reported hearing explosions in the Syrian capital, where more than a million people live. "Assad might have used chemical weapons this time, but he's been indiscriminately targeting civilians for years".
Defence officials from the countries involved in the attack gave differing accounts of how much warning was given to the Russians, Syria's powerful ally.
Lawrence Corb with the Center for American Progress told VOA that the participation of Britain and France in the strikes may cause Russia to have some "second thoughts" because "the last thing the Russians want is to provide an excuse for the United States and its North Atlantic Treaty Organisation allies to get involved (in Syria) because (Russia's) objective is to keep Assad in power". "They are crimes of a monster instead", Trump said.
Mr Trump said the Syrian regime's use of chemical weapons on Douma was a "significant escalation in a pattern of chemical weapons use by that very bad regime".
The defense sources did not say where the B-1s flew from, but Air Force media earlier this month showed the bombers arriving at the Al Uldeid US air base in Qatar, on the Arabian peninsula. "And great warriors they are".
Syrian government forces had taken precautions at military bases throughout the week in anticipation of possible strikes.
"It adds much further to the pressure not just imposed on Damascus, but most importantly on Russian Federation", he said. This has raised fears of a possible direct clash of USA and Russian forces.
Dunford said the US had identified its targets to mitigate the risks of Russian forces being involved, but the USA military did not coordinate Friday's operation with the Russians nor did it notify them beforehand.