Some 180 civilians have been killed in flare-up since April 30, according to Syrian Observatory for Human Rights, a British-based monitor.
Washington: The United States on Tuesday warned the Syrian government over carrying out chemical attacks as a counter-offensive, particularly in its northwestern region, the remaining holdout of the Islamic State.
In a statement, the US State Department said, "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, 2019."
"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," the statement read.
Washington continues to investigate the suspected attack in northwest Syria that is believed to be "part of a violent campaign led by President Bashar al-Assad."
The State Department alleged that the attack violates a ceasefire in the greater Idlib area that has protected millions of civilians who were already displaced from violence in other parts of the war-ravaged country.
"The United States reiterates its warning, first issued by President Donald Trump in September 2018, that an attack against the Idlib de-escalation zone would be a reckless escalation that threatens to destabilise the region," the department added.
Similarly, on November 24, 2018, the Assad regime and Russia attempted to fabricate a chemical weapons attack near Aleppo and blame it on opposition forces, 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. The former Organisation for the Prohibition of Chemical Weapons (OPCW)-UN Joint Investigation Mechanism repeatedly verified and reported the Assad regime's use of chemical weapons, it added.
The warning came despite a trip to Russia last week by US Secretary of State Micheal R Pompeo, who voiced optimism that the rival powers had found ways to work together on Syria.
Some 180 civilians have been killed in the flare-up since April 30, according to the Syrian Observatory for Human Rights, a British-based monitor. The United Nations says that tens of thousands have fled their homes.
International inspectors say that Assad's forces have carried out a series of chemical attacks in the course of the brutal civil war, which has killed more than 370,000 people and displaced millions since 2011, The News International reported.