Russian Prime Minister Dmitry Medvedev on Friday declared that the country would treat any further sanctions imposed on it by the United States as a “declaration of economic war”, AFP reported.

The warning came days after the US announced a new round of sanctions on Russia for its alleged use of a nerve gas agent in an attempt to poison former double agent Sergei Skripal and his daughter Yulia in England.

“I would not like to comment on talks about future sanctions, but I can say one thing: If some ban on banks’ operations or on their use of one or another currency follows, it would be possible to clearly call it a declaration of economic war,” Reuters quoted Medvedev as saying. “And it would be necessary, it would be needed to react to this war economically, politically, or, if needed, by other means. And our American friends need to understand this.”

Medvedev said that Russia has survived economic restrictions many times in its history and has never given in to pressure, reported RT Network. “Our country had been living under constant pressure through sanctions for the last hundred years. Nothing has changed,” he said.

On Thursday, the Russian currency fell to its lowest dollar value in almost two years, plummeting to 66.70, according to the CNBC. Russia had criticised the sanctions as “categorically unacceptable”, reported CBS News.

The new sanctions will take effect on or around August 22, and relate to exports of electronic components and other technologies. The state department said “more draconian” sanctions will follow within three months if Russia does not give assurances that it will not use chemical weapons and allow on-site inspections by the United Nations.

On March 4, Skripal and his daughter were found unconscious on a park bench outside a shopping centre in Salisbury. They recovered after weeks of treatment. The poisoning led to a major diplomatic controversy globally. The UK and its allies, including the European Union and the North Atlantic Treaty Organisation, accused Moscow of involvement in the incident and expelled 23 Russian diplomats from their territory. The US expelled 60 suspected Russian spies after the incident.

Russia has repeatedly denied claims that Novichok, the nerve agent used to poison the pair, was developed in the country or the Soviet Union.