Low credit ratings issued against a Russian economy crippled by low oil prices and sanctions are part of a Western economic war, a Kremlin official said Friday.

Russian Foreign Ministry spokesman Alexander Lukashevich said credit downgrades are based on the political motives of Western powers frustrated with Kremlin policies.

"The use of targeted and deliberate downgrades of ratings of Russian companies and the sovereign rating of the country has become a part of the U.S. and EU economic war against us," he said.

Standard & Poor's in January cut Russia's foreign currency rating to junk status. Russia's currency, the ruble, continues to lose value, trading Friday at 67 to the U.S. dollar, down about 6.25 percent from the start of the year.

Low oil prices and pressure from Western economic sanctions imposed in response to the Kremlin's stance on crises in Ukraine are diminishing government finances.

A December report from the World Bank said Russia's economy is expected to contract by 0.7 percent in 2015. Low oil prices are expected to weigh on investment decisions and the industry itself should decline because of a steady decline in consumption.

Earlier this week, Russian Natural Resources Minister Sergei Donskoy said government support for exploration may be 15 percent less than last year, which may curb future developments in the upstream sector.

Foreign ministers from the European Union agreed in late January to extend existing sanctions against Russian until September.