US Defence Secretary Jim Mattis said Friday that chlorine gas was known to have been weaponised "repeatedly" in attacks in Syria lately.
Assad is believed to have secretly kept part of Syria's chemical weapons stockpile despite a US-Russian deal under which Damascus was supposed to have handed over all such weapons for destruction in 2014, the US officials said.
Mr Assad's forces have instead "evolved" their chemical weapons and made continued occasional use of them in smaller amounts since the attacks previous year, the officials told reporters in a briefing.More news: Trump expected to announce order to keep Guantanamo Bay prison open
Secretary of State Rex Tillerson said at the time the us had "very high confidence" that the chemical agent used in that deadly attack was sarin nerve gas. Nearly all independent analysts and investigators agree the Syrian regime is the culprit of the chemical attacks.
Mattis told reporters that chlorine gas was known to have been weaponised in attacks in Syria, but added: "We are even more concerned about the possibility of sarin use".
Assad's chemical weapons could spread to "US shores" the official said, should the worldwide community not respond quickly to limit Assad, warning that "it will spread if we don't do something".
"It will spread if we don't do something", warned an official who wanted to remain anonymous.More news: Hyundai released new generation advanced SUV Santa Fe design sketch
A second official said, however, that the Trump Administration hopes that stepped-up worldwide sanctions and diplomatic pressure will help rein in Assad's chemical weapons programme. The Islamic State (ISIS) group continues to use them, they said, although the jihadists' arms are said to be more rudimentary. The officials noted that the underlying chemicals are easy to acquire or produce, and said the US does not believe ISIS has gotten a hold of military stockpiles in either Iraq or Syria.
Nauert's comments follow a suspected chlorine gas attack in the rebel-held territory of Eastern Ghouta, on the outskirts of Damascus, on Thursday. In a site located on the outskirts of capital Damascus, at least three civilians were killed and many others left injured, according to the White Helmets.
The reports could not be independently verified and the Britain-based Syrian Observatory for Human Rights, which monitors the war in Syria via activists on the ground, was unable to confirm the reports either.More news: $600 Million in Cryptocurrency Crimes Uncovered In South Korea
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