Russia threatened Tuesday that it might halt its assistance on critical international issues if the U.S. continues its strategy of economic sanctions against Moscow.
"The actions by the United States are putting in doubt the prospects of bilateral cooperation on solving the situation around the Iranian nuclear program, the Syrian crisis and other acute international problems," Russias Foreign Ministry said in a statement.
"As Washington could have seen previously, we don't leave such unfriendly acts without an answer," the ministry added.
The terse statement comes a day after the U.S. Treasury Department announced it would impose sanctions on four more Russians for alleged human rights abuses, including two law enforcement officials believed to have covered up the death of a prominent anti-corruption lawyer while he was held in prison.
The ministrys statement marks latest backward step in the relationship between Washington and Moscow. Relations have deteriorated steadily since Russia annexed Crimea last spring and gave its support to separatist rebels in eastern Ukraine.