New EU sanctions against Russia have gone into force, blocking loans for five big state banks and curbing EU business with oil and defence firms, the BBC reports.
The aim is to keep pressure on Russia over its role in the Ukraine crisis. But the measures could be eased or lifted if a ceasefire in Ukraine holds.
Russia says it is preparing a response. One top Russian official said cars imported from the EU could be targeted.
Nato says Russia still has about 1,000 heavily armed troops in east Ukraine.
US President Barack Obama said his country would join the EU in imposing tougher sanctions on Russia, targeting the defence, finance and energy sectors. He said he would provide details on Friday.