The European Union has agreed to impose further sanctions on Russia on Friday over its role in the Ukraine crisis, diplomats say.
The move is aimed at maintaining pressure on Russia, the sources said.
Russia says it is preparing a response “commensurate with the economic losses” caused by the EU sanctions.
Nato says Russia still has about 1,000 heavily armed troops in eastern Ukraine – where pro-Russian rebels are fighting – and about 20,000 near the border.
The new sanctions are expected to tighten access to Western loans, especially for big Russian state oil companies, and expand a blacklist of Russian officials subject to visa bans and asset freezes. More rebel leaders will also go on that list.
Russian Foreign Ministry spokesman Alexander Lukashevich called the new sanctions “an absolutely unfriendly step”.
The EU decision followed a conference call involving a number of European leaders, including UK Prime Minister David Cameron.
The member states struggled to agree on how to factor in the fragile truce between Ukrainian troops and pro-Russian rebels. It took effect on 5 September and appears to be holding despite some sporadic shooting.
The rouble fell to a new low of 37.57 to the dollar on Thursday, after news about the EU sanctions broke. It also fell against the euro.