BRUSSELS: The EU's top court on Thursday rejected an appeal by Russia's state-controlled oil giant Rosneft against swingeing sanctions imposed over the Ukraine crisis, ruling the measures were "duly justified".

A number of companies that are part of Rosneft wanted the cancellation of the 2014 sanctions, which restrict their access to capital markets and bar EU companies from selling them certain goods and equipment.

After losing in the lower General Court of the EU, Rosneft appealed to the European Court of Justice, but judges in the higher tribunal threw out the appeal.

"The measures have been duly justified and are suitable for putting pressure on Russia because of its role in that crisis," the Luxembourg-based court said in a statement.

"The Court of Justice dismisses the companies' appeal in its entirety."

The EU introduced the sanctions as part of measures to punish the Kremlin for the annexation of Crimea and for its support for pro-Moscow separatists in eastern Ukraine.

Last week the bloc extended sanctions against 175 people and 44 entities deemed to undermine Ukrainian territorial integrity.

The EU also has broad economic sanctions in place against Russia over Malaysian Airlines flight MH17, which was shot down over Ukraine in July 2014, killing 298 people, an attack the West blamed on pro-Russian rebels.

More than 13,000 people have been killed since the rebel insurgency broke out in the eastern Donetsk and Lugansk regions in April 2014 following Russia's annexation of Crimea from Ukraine.

Kiev and its Western allies accuse Russia of funnelling troops and arms across the border. Moscow has denied the claims despite evidence to the contrary.