Assad preparing new chemical weapons attack in Syria, White House claims

Syrian President Bashar al-Assad may be preparing another chemical weapons attack, one that would result in the "mass murder" of civilians, the White House said on Monday, warning the regime would pay a "heavy price" if it went ahead with such an assault.

The White House said in a statement released late on Monday the preparations by Syria were similar to those undertaken before a 4 April chemical attack that killed at least 80 civilians in the town of Khan Sheikhoun and prompted US President Donald Trump to order a cruise missile strike on a Syrian air base.

That assault with 59 Tomahawk missiles marked the first direct US attack on the Syrian regime and Trump's most dramatic military action since he took power in January.

"The United States has identified potential preparations for another chemical weapons attack by the Assad regime that would likely result in the mass murder of civilians, including innocent children," White House spokesman Sean Spicer said.

"If ... Mr. Assad conducts another mass murder attack using chemical weapons, he and his military will pay a heavy price," he said.

The unusual public warning on Monday night appeared to be intended to deter the regime from repeating its use of chemical weapons against rebel-held cities and towns. It may also have been aimed at the regime’s backers in Moscow and Tehran, who have resolutely backed Assad and denied the regime’s responsibility for chemical weapons use.

The US ambassador to the UN, Nikki Haley, tweeted: “Any further attacks done to the people of Syria will be blamed on Assad, but also on Russia and Iran who support him killing his own people.”

Russia has supported the Syrian regime since 2015 with air strikes against what it says are Islamist extremists.