Trump presidency calls for global front against chemical weapons after criticisms of his predecessor

White House statement to mark fourth anniversary of deadly gas attack in Damascus suburb warns of unspecified 'serious consequences' for any regime using chemical weapons

A civil defence member breathes through an oxygen mask, after the gas attack in the town of Khan Sheikhun in April. Ammar Abdullah / Reuters

The United States on Monday called for a united international front against the use of chemical weapons to mark the fourth anniversary of a deadly attack by the Syrian regime that left 1,400 people dead.

“It is critical that the international community not forget these tragic events,” according to a White House statement. “We must speak with one voice and act with one purpose to ensure that the Syrian regime, and any other actor contemplating the use of chemical weapons, understands that doing so will result in serious consequences.”

The statement did not clarify the nature of the “serious consequences” if a regime used chemical weapons during a Trump presidency.

President Trump has been critical of his predecessor for ‘weakness’ and 'irresolution' after Barack Obama failed to use military force after describing the use of chemical weapons by the Syrian regime as a “red line” in 2012.

The former president drew back from military action a year later following the 2013 attack on the Damascus suburb of Ghouta, instead striking a deal, brokered by Russia, which saw the bulk of Syria’s supplies of the lethal nerve agent sarin removed from the country.

The Bashar Al Assad regime has used chlorine gas and sarin during the Syrian civil war with deadly effect. The most recent use of chemical weapons was on the northern town of Khan Sheikhun that carried the hallmarks of a sarin attack.

The White House statement said that the Khan Sheikhun attack showed that Assad “still possesses these heinous weapons and is willing to use them against innocent civilians”.

The statement added: “We reiterate our call for all countries to stand together and leave no doubt that the use of chemical weapons will not be tolerated.”