"Everyone is going to feel it at this point", Haley said, warning of consequences for Assad's foreign allies. "We have to be conscious of the fact that we can't allow even the smallest use of chemical weapons".
The U.S. has raised the prospect of more sanctions against Russian Federation.
It was "shameful" that a lack of accountability for the April 2017 attack on Khan Sheikhun "can only have reassured the Syrian regime that the worldwide community was not serious in its stated commitment to uphold the norm against chemical weapons use", he added.
But Syria and its ally Russian Federation have sought to downplay the impact of the subsequent airstrikes, saying Syrian air defenses shot majority down.
One of the things that I thought the administration was likely to do that I think because of concern about involvement of Russian Federation in the region - of potential retaliation by Russian Federation - they limited their restraint from doing, which would have been to impose a penalty on the Syrian conventional forces such that every time Bashar al-Assad uses chemical weapons, we destroy more and more of his conventional military capability.
"There is the need to give a push to the United Nations -led process", Mogherini said.
She authorized the strikes without parliamentary backing and it's not clear she would have got it if she'd sought it. Parliament refused United Kingdom participation in a planned punitive raid on Syria in 2013, one of the reasons then-U.S. President Barack Obama called it off.
"Right now they don't have very good friends and right now the friends that they do have are causing them harm", Haley said, referring to Russian Federation.
"I think everyone knows that we sent a strong message, and our hope is that they listen to it", she told CBS News on Sunday.
Johnson added there was no proposal in place for further attacks, but if Assad's regime were to repeat chemical attacks "clearly, with allies, we would study what the options were". Iran's Supreme Leader called the attack a crime and the country's Revolutionary Guard Corps said it gave "the resistance a more open hand", although it did not threaten to retaliate.
Algeria, Egypt regret Western air strikes against Syria
Moscow condemned the Western states for refusing to wait for OPCW's findings before attacking. Mr Corbyn warned of an escalation in a "proxy war" between the USA and Russian Federation .
Russian Federation has military forces, including air defences, in several areas of Syria to support Mr Assad in his long war against anti-government rebels.
The UN security council's 15 members will meet on Monday to discuss a call for a wider push to eliminate the covert Syrian government stockpiles.
It marked the second time that the Trump administration has attacked Syria for its alleged use of chemical weapons since last April, when Washington fired 59 Tomahawk cruise missiles.
US defense officials say they have high confidence chlorine gas was used and are still assessing evidence indicating the presence of sarin gas.
"Good souls will not be humiliated", Mr Assad tweeted, while hundreds of Syrians gathered in Damascus, the capital, where they flashed victory signs and waved flags in scenes of defiance after the early morning barrage.
Syrian media and locals reported air strikes and Syrian air defense launching rockets in response in the early hours of Tuesday.
Western states have blamed the Syrian government forces for the incident, but Damascus has denied using chemical weapons.
Although officials said the singular target was Assad's chemical weapons capability, his air force, including helicopters he allegedly has used to drop chemical weapons on civilians, were spared.
USA ambassador Nikki Haley warned her United Nations counterparts that although the mission was designed as a one-off, that did not preclude further action against Mr Assad.
According to United States officials, the operation comprised three U.S. destroyers, a French frigate and a USA submarine. "And we can not wait to alleviate further humanitarian suffering caused by chemical weapons attacks".