The message-for-message spat between Washington and Moscow continues apace, after Russia reminded President Trump that the US still hasn’t got rid of its chemical weapons stockpile.

“Our relationship with Russia is worse now than it has ever been, and that includes the Cold War. There is no reason for this. Russia needs us to help with their economy, something that would be very easy to do, and we need all nations to work together. Stop the arms race?” Donald Trump tweeted on Wednesday morning.

Our relationship with Russia is worse now than it has ever been, and that includes the Cold War. There is no reason for this. Russia needs us to help with their economy, something that would be very easy to do, and we need all nations to work together. Stop the arms race? — Donald J. Trump (@realDonaldTrump) April 11, 2018

To which Maria Zakharova, the spokesperson of the Russian Foreign Ministry, shot back on her Facebook page: “Great idea. Let’s start by getting rid of chemical weapons. American ones.”

After signing the Chemical Weapons Convention (CWC) in 1997, the US pledged to destroy its chemical weapons stockpile – the second biggest in the world – by 2012. After repeatedly missing the deadline, it now promises to do so by 2023.

Russia, which once owned more chemical weapons than any other state, declared itself free of them in 2017.

READ MORE: Moscow to Trump: Are ‘smart’ missiles an attempt to destroy alleged chem attack evidence in Syria?

Earlier on Wednesday, Trump urged Russia “to get ready” for “nice, new and ‘smart’” missiles to rain down on Syria, in response for the alleged chemical attack on Douma on April 7. In turn, Zakharova wondered if Washington plans “to cover up all evidence of this fabricated attack with smart missile strikes, so that international inspectors had no evidence to look for?”