Russia's Foreign Ministry has vowed retaliation against the United States for expanded sanctions over the Ukraine crisis.
"The United States has once again demonstrated that it has made a choice in favor of escalating confrontation," the ministry said on July 31.
"Such provocative actions not only destroy U.S.-Russian relations; they also hinder collaboration in solving other global problems," it said. "Of course this will not be left without a reaction from us."
Kremlin spokesman Dmitry Peskov said Russia could retaliate on a symmetrical basis, as it has in the past, or this time the countermeasures could be harsher.
"Unfortunately these steps will bring about nothing but negativity," he said.
The United States on July 30 expanded its sanctions to include individuals who have "provided support" to reputed friends of Russian President Vladimir Putin, as well as former officials of Ukraine's ousted leader Viktor Yanukovych, and others.
Two Russian weapons producers -- Kalashnikov and Izhmash -- and several companies operating in Crimea were also targeted.
U.S. officials have described the new sanctions as "refinements" needed to prevent people and companies targeted earlier from getting around the sanctions.