"The hostility and unpredictability of America's actions force us in general to be prepared for the worst scenarios," Kremlin spokesman Dmitry Peskov told reporters.
Moscow's ties with Washington nosedived last month when Russia recalled its ambassador after US President Joe Biden said he thought President Vladimir Putin was a killer.
The rouble was 0.7% weaker against the dollar at 76.18, a whisker away from a one-week low and heading further from the more than one-week high of 75.22 hit in the previous session.
It had lost 0.8% to trade at 89.46 versus the euro .
Russian assets have been under pressure since last week as markets prepared for a new round of US sanctions over alleged election meddling, which Moscow has denied.
The rouble gained 0.2% to 90.30 against the euro , hovering away from the 87 mark seen before the threat of new sanctions intensified.
"They are merciless," EU foreign policy chief Josep Borrell told the European Parliament after visiting Moscow last week to plead for the release of Kremlin critic Alexei Navalny.
The current power structure in Russia, combining vested economic interests, military and political control, leave no opening for democratic rule of law.