"When you kill innocent children, innocent babies - babies, little babies - with a chemical gas that is so lethal - people were shocked to hear what gas it was - that crosses many, many lines, beyond a red line", Trump had said during a news conference Wednesday referring to the attack that was allegedly carried out by the Syrian government.
"If you look at his actions, if you look at the situation, it's going to be hard to see a government that's peaceful and stable with Assad", said Haley.
British Foreign Secretary Boris Johnson said he had canceled a scheduled April 10 visit to Moscow as developments in Syria "have changed the situation fundamentally". But it's now vitally important we develop a strategy, we put that strategy in motion, and we bring about peace in the region.
The top priority for the United States in Syria is to defeat Daesh, said Secretary of State Rex Tillerson said at a TV interview on Sunday.
He said the United States expected Russian Federation to take a tougher stance against Syria by rethinking its alliance with Assad because "every time one of these horrific attacks occurs, it draws Russian Federation closer into some level of responsibility".
Sen. Rand Paul (R-Ky.), who has often expressed libertarian sentiments on issues related to US military intervention, cautioned that should the Assad regime collapse-a terrorist entity might fill the power vacuum.
Prior to the attack in Khan Sheikhun, Tillerson said Assad's fate should be decided by the Syrian people, suggesting Washington would not oppose him standing for reelection. "You pick and choose your battles and when we're looking at this, it's about changing up priorities and our priority is no longer to sit there and focus on getting Assad out", she told reporters.
The Syrian foreign minister denied the government's involvement in the Idlib incident, saying it had never nor would it ever use chemical weapons on either civilians or terrorists operating in the country.
Hundreds more suffered symptoms that the World Health Organization said were in some cases consistent with exposure to chemicals that include nerve gas.
Syria has received substantial military aid from Russian Federation since the Cold War and Moscow strongly condemned the attack on the airfield as "Trumped-up".
Russian Federation "agreed to be the guarantor of the elimination of the chemical weapons and why Russian Federation has not been able to achieve that is unclear to me", Tillerson added.
Asked whether she thought Russian Federation was trying to help Assad cover up the use of chemical weapons, Haley said either Moscow knew Assad had weapons that would be used or they were "played for fools by Assad and kept in the dark".
Dozens of representatives of the media, local authorities, and emergency services have visited the airfield since the attack, with no alleged "storage units" or chemical weapon shells being found, the ministry said in a statement, calling on a mission of professional experts to be sent to the air base.