Russian oil giant Rosneft and a close associate of President Vladimir Putin are fighting the EU in court over sanctions imposed on some of Russia's biggest companies, an official website indicated Friday.
A Russian billionaire, Arkady Rotenberg, who is also Putin's judo sparring partner, filed two suits at the European Union's Court of Justice in Luxembourg, while state-owned Rosneft filed one.
The suits were filed last week, the website indicated, and were first reported by the Financial Times.
According to procedure, the argumentation in the suit will not be made public for two months.
Contacted by AFP in Moscow, both Rosneft and a spokesman for Rotenberg refused comment.
The suits follow the EU's tough new package of economic sanctions against Russia decided last summer.
The latest measures targeted major Russian energy, finance and defence companies including Rosneft and weapons manufacturer Kalashnikov.
The bloc also placed asset freezes and visa bans on a host of Russian figures close to Putin as well as rebels in Ukraine and annexed Crimea.
Russian banking giant VTB -- also targeted by sanctions --- said it was considering whether to take legal action.
A spokeswoman for VTB told AFP bank lawyers were "thoroughly studying the issue."
The EU sanctions adopted in September are a toughening-up of measures adopted in July after the shooting down of Malaysia Airlines flight MH17 over rebel-held east Ukraine.
The European Council, representing the EU member states, said it would defend the measures which were "imposed over Russia's role in destabilising eastern Ukraine".
"The council takes great care to ensure legal robustness when adopting restrictive measures and takes due account of relevant case-law of the court," it said.