The rouble, which had hit a 10-month high on Thursday, fell on Friday to 63.79 against the US dollar before recovering to 63.27 shortly after.

In a statement released on their website, the so-called Blue Dog Democrats said the measures would increase sanctions on Russia's sovereign debt, certain Russian banks, the cyber sector, Russian LNG investments for projects outside of Russia, and on various individuals acting on behalf of President Vladimir Putin.

"Another escalation of tensions between Russia and the US over allegations that the Kremlin interfered in the US presidential elections...that is the reason for the rouble spike," said Piotr Matys, FX strategist for central and eastern Europe at Rabobank in London.

Matys added that the risk of more sanctions on Russia, however, "hasn't prevented the rouble from being the best performing EM currency year-to-date."

The rouble this week had received support from strong demand for weekly treasury bond auctions, as well as from month-end taxes that often prompt export-focused companies to convert their foreign currency to meet local duties.

The Russian currency reached its strongest level since August 2018 on Thursday in part because of US Federal Reserve signals it could cut rates to support the economy.

The prospect of a key rate cut by the US Federal Reserve would increase demand for emerging market currencies as investors look for higher-yielding assets.

Oil prices, which often buttress the Russian currency, were up on Friday on fears of a military confrontation between Tehran and Washington.

Russian stock indexes were also down on Friday.

The dollar-denominated RTS index was down 1.4pc to 1372 points, while the rouble-based MOEX Russian index was 0.8pc lower at 2,759 points.