The US is warning that it'll strike the Syrian regime hard if they use chemical weapons again

Reuters

A Civil defence member carries an injured man amid dust after an airstrike in the besieged town of Douma in Eastern Ghouta in Damascus, Syria, February 7, 2018.

• The White House warned Russia, Iran and the Syrian regime on Tuesday that the US would retaliate if either the regime used chemical weapons in a new offensive.
• Since at least 2013, the Assad regime has been repeatedly accused of using chemical weapons in multiple Syrian provinces, with the most recent one coming in April. 
• The US, the UK and France responded to the alleged chemical attack then, in Eastern Ghouta, with multiple airstrikes, but the strikes had minimal effect.

The White House warned the Syrian regime and their allies Russia and Iran on Tuesday that the US would retaliate if either they used chemical weapons on the last rebel stronghold in Syria's Idlib province. 

"Let us be clear, it remains our firm stance that if President Bashar al-Assad chooses to again use chemical weapons, the United States and its Allies will respond swiftly and appropriately," Press Secretary Sarah Sanders said in a statement.

"President Donald J. Trump has warned that such an attack would be a reckless escalation of an already tragic conflict and would risk the lives of hundreds of thousands of people," Sanders added. 

Since at least 2013, the Assad regime has been repeatedly accused of using chemical weapons in multiple Syrian provinces, with the most recent one coming in Eastern Ghouta in April. 

Russia and the Syrian regime have denied using chemical weapons, often arguing that the West or militants staged the attacks. 

The US, the UK and France responded to the alleged chemical attack in Eastern Ghouta with multiple airstrikes, but the strikes had minimal effect.

In the end, the Syrian regime drove the rebel group Jaysh al-Islam from Eastern Ghouta, raising questions about how far the US is willing to go to stop the alleged chemical attacks.

On Tuesday, Russia began conducting airstrikes once again on Idlib, according to the Washington Post, raising fears that a full-on assault would soon begin. 

Assad and Russia have had their sights set on Idlib for months, but an all-out attack has yet to be launched. 

"The Turks are blocking the offensive," Jennifer Cafarella, a senior intelligence planner at the Institute for the Study of War, previously told Business Insider. "The Turks and Russians continue to frame their discussion from the lens of cooperation, but that's not actually what's happening."

Cafarella said that Turkey may allow a partial offensive in Idlib, but that Ankara can't afford "to have another massive Syrian refugee flow towards the Turkish border."