The White House has warned the Syrian regime it will “pay a heavy price” if claims of the government preparing for another chemical attack prove to be true.

In an ominous statement released by US press secretary Sean Spicer on Monday (US time), the White House has identified “potential” evidence the Syrian government was preparing for a second major chemical weapons attack.

“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,” the statement read.

“The activities are similar to preparations the regime made before its April 4, 2017, chemical weapons attack.

“As we have previously stated, the United States is in Syria to eliminate the Islamic State of Iraq and Syria. If, however, Mr Assad conducts another mass murder attack using chemical weapons, he and his military will pay a heavy price.”

Syrian President Bashar al-Assad. Photo: AAP

The White House threatened Syrian President Bashar al-Assad that there would be consequences, should the regime conduct such an attack.

The US ambassador to the United Nations, Nikki Haley, tweeted that “any further attacks done to the people of Syria will be blamed on Assad, but also on Russia & Iran who support him killing his own people”.

In April, the Syrian government received global condemnation after a chemical weapons attack killed at least 58 civilians, including about 11 children, and wounded dozens in rebel-held territory.

Victims showed signs of suffocation, convulsions, foaming at the mouth and pupil constriction, the Associated Press reported.

The White House publicly blamed the Syrian government for the “reprehensible” act, despite Syria denying it carried out the attack.

The United States responded with missile strikes against the Syrian government-controlled air base, Shayrat, actions which were backed at the time by Australian Prime Minister Malcolm Turnbull.

It was President Trump’s most significant military order since coming in to office.

Meanwhile, Russian President Vladimir Putin, a close ally of Mr Assad, criticised the US’s retaliatory strike.

Mr Assad told the AFP news agency in an interview earlier this year that the April attack was “100 per cent fabrication” used to justify a US air strike.

At the time of the assault, US officials declared the intervention a “one-off” aimed at deterring future chemical weapons attacks.

US Defence Secretary Jim Mattis has previously said there was “no doubt” the Syrian government still had chemical weapons in its possession.

The White House has provided no immediate evidence to back up its claims of the current build-up.