Russia has warned it will consider a tit-for-tat response to new US sanctions.
Yesterday the US said it will impose new sanctions on Moscow, accusing Russia of responsibility for the Salisbury attack.
Former Russian spy Sergei Skripal and his daughter Yulia were poisoned with Novichok in March in the English city.
It left both critically ill, although they were later discharged from hospital after weeks of treatment.
Responding to the newly announced US sanctions, a Russian foreign ministry spokesperson - quoted by the TASS news agency - said: "The US is intentionally choosing the path of a further deterioration of bilateral relations, which have been nearly reduced to zero thanks to its efforts.
"The Russian side will engage in working out retaliation measures to a new unfriendly move by Washington."
Meanwhile, Dmitry Polyanskiy - a Russian representative to the UN - described the situation as the 'theatre of the absurd'.
The theater of absurd continues. No proofs, no clues, no logic, no presumption of innocense, just highly-liklies. Only one rule: blame everything on Russia, no matter how absurd and fake it is. Let us welcome the United Sanctions of America! #SkripalHoax https://t.co/MekROW5WBc
— Dmitry Polyanskiy (@Dpol_un) August 8, 2018
The British government and many of its allies have blamed Russia for the Salisbury attack, and several countries - including Ireland - expelled Russian diplomats in response.
The Kremlin denies being behind the attack, and reacted with tit-for-tat diplomatic expulsions.
In a statement last night, the US State Department claimed Russia 'attempted to assassinate' the Skripals.
Citing US legislation on chemical and biological weapons, a spokesperson said "the Government of the Russian Federation has used chemical or biological weapons in violation of international law or has used lethal chemical or biological weapons against its own nationals."
Congress in Washington will now be notified of the fresh sanctions, with the sanctions set to come into effect on August 22nd.