The US State Department announced Tuesday it believes the Syrian government may be using chemical weapons on civilians again and warned that America and its allies will respond "quickly and appropriately" if they were proven right.
The Syrian government is accused of conducting an alleged chlorine attack on Sunday in northwest Syria.
"Unfortunately, we continue to see signs that the Assad regime may be renewing its use of chemical weapons, including an alleged chlorine attack in northwest Syria on the morning of May 19," State Department spokeswoman Morgan Ortagus said in a statement.
"We are still gathering information on this incident, but we repeat our warning that if the Assad regime uses chemical weapons, the United States and our allies will respond quickly and appropriately," she said.
Ortagus said Sunday's attack was a direct violation of a ceasefire agreement set in place to protect civilians in the Idlib area. In April, Syrian and Russian forces launched a heavy bombing campaign in Idlib and the Hama Province. The Syrian Observatory for Human Rights said the bombing has killed approximately 223 civilians since it began.
The State Department urged Assad to stop the attacks.
"The regime's attacks against the communities of northwest Syria must end," Ortagus said. "The United States reiterates its warning, first issued by President Trump in September 2018, that an attack against the Idlib de-escalation zone would be a reckless escalation that threatens to destabilize the region."
President Donald Trump ordered air strikes and missile attacks in April 2018 after the Syrian regime carried out a chemical weapons attack near Damascus that killed 40 people.
In April 2017, America fired missiles at a Syrian airbase after Syrian forces conducted a chemical attack that killed at least 80 civilians.
The State Department statement also accused Russia and the Syrian government of "a continuing disinformation campaign ... to create the false narrative that others are to blame for chemical weapons attacks."
"The facts, however, are clear," the statement said. "The Assad regime itself has conducted almost all verified chemical weapons attacks that have taken place in Syria — a conclusion the United Nations has reached over and over again."