“There are threats of attacks on shopping centres, railway and metro stations and other public gathering places in major urban areas, including Moscow and Saint Petersburg, as well as in areas of heightened tension on Russia’s border with Ukraine,” the embassy said.
“Review your personal security plans… so you have no plans to leave, and don’t rely on US government assistance,” she added.
Russian Foreign Ministry spokeswoman Maria Zakharova questioned whether the United States had passed on information about possible attacks to Russia.
“If not, how can one understand all this?” she said.