UPDATE: 4:10 a.m. EDT — British Defense Secretary Michael Fallon said Tuesday the United Kingdom will back the United States in its action against Syria to stop any possible chemical attacks by President Bashar Assad’s regime. The comments came after the White House Press Secretary Sean Spicer said late Monday that Washington found possible evidence of the Assad regime preparing for a new chemical attack.

“We’re very clear what our position is. The use of chemical weapons by Syria is absolutely abhorrent. The last time the United States took action to deal with the aircraft and airbase from which the attacks were launched, we fully supported the action,” Fallon said on BBC Radio 4’s Today show, according to Financial Times.

Original story:

The White House Press Secretary Sean Spicer warned late Monday the President Donald Trump administration will make Syrian President Bashar Assad and his military “pay a heavy price” if his regime carries out another deadly chemical attack in the war-torn country. While Spicer said the U.S. found possible evidence of Syria readying for a new chemical attack, defense officials reportedly said they do not know what prompted the White House to issue such a statement.

“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 activities are similar to preparations the regime made before its April 4, 2017, chemical weapons attack,” Spicer said in a statement Monday.

Read: John McCain Blames Trump Administration Over Syria Chemical Attack

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

Despite issuing the statement, the White House did not provide any immediate evidence to support its claims. No other official from the Trump administration commented on the statement.

Meanwhile, five defense officials told BuzzFeed News they had “no idea” where the likely chemical attack would come from. They also reportedly said they did not know why the White House released such a statement.

Nikki Haley, the United States Ambassador to the United Nations, reacted to the White House’s statement on Twitter.

Assad’s regime was blamed for the April 4 chemical attack in Syria’s Idlib province that killed at least 80 civilians, including several children. However, the Syrian president rubbished the claims and blamed the opposition fighters for the attack. At the time of the incident, Russian Defense Ministry said the chemical gas was released during a Syrian airstrike on a rebel chemical weapons arsenal and munitions factory.

Read: Ivanka Trump Behind Syria Airstrikes?

On April 6, Trump ordered missile strikes into the government-controlled Shayrat air base in the troubled country.

"It [the chemical attack] crossed a lot of lines for me. When you kill innocent children, innocent babies — babies, little babies — with a chemical gas that is so lethal — people were shocked to hear what gas it was — that crosses many, many lines, beyond a red line," Trump had said prior to the missile strikes.

The airstrikes were widely condemned by Russia and Iran. Russian President Vladimir Putin called the airstrike an "aggression against a sovereign nation" and viewed it as an "attempt to distract the world from civilian casualties  caused by the U.S. military action in Iraq." The move did "significant damage to U.S.-Russia ties," Putin's spokesman Dmitry Peskov reportedly said at the time.

“Not even two decades after 9/11, the U.S. military fighting on the same side as al Qaeda & the Islamic State (ISIS) group in Yemen & Syria. Time to stop hype and cover-ups,” Iranian Foreign Minister Mohammad Javad Zarif said on Twitter on April 7.