Former majority owners of Yukos Oil Co. won a landmark $50 billion award against Russia for the confiscation of what was once the nation’s largest oil company after a decade-long battle.

The Permanent Court of Arbitration in The Hague ruled that Russia is liable to pay almost half of the $103 billion plus interest they sought, GML Ltd., the holding company for Yukos’s former main shareholders, said today. The decision showed Russia’s campaign against Yukos was “politically motivated,” GML head Tim Osborne said in London.

The decision against Russia marks a fresh headache for President Vladimir Putin, who faces intensifying U.S. and European sanctions aimed at forcing him to end the conflict in neighboring Ukraine. Collecting may take years of wrangling, according to former Yukos legal counselor Dmitry Gololobov.

“A superpower like Russia has been unanimously held accountable for its violation of international law by an independent arbitration tribunal of the highest possible repute,” Emmanuel Gaillard, one of GML’s lawyers, said in London. “Today is a great day for the rule of law.

Russia must pay the award by mid-January or face penalties, according to GML. The possibility for appeal is limited to ‘‘technical’’ grounds within the Dutch courts, Gaillard said.

Khodorkovsky, Yukos

The decision risks dragging Russia’s two biggest companies, oil producer OAO Rosneft and natural gas exporter OAO Gazprom, into extended legal battles. The state-controlled companies’ assets may be targeted because they were beneficiaries of expropriated Yukos assets, said another GML lawyer, Yas Banifatemi. Rosneft and Gazprom both declined about 2 percent in Moscow trading.

Putin’s government dismantled Yukos in 2004 to 2007 over $27 billion in tax charges after imprisoning Chief Executive Officer Mikhail Khodorkovsky. The former owner, who isn’t party to the award, said in a statement today that it was ‘‘fantastic that the company shareholders are being given a chance to recover their damages.”

Most of its former assets were acquired in a series of forced sales by Rosneft, which has since become the world’s largest publicly traded oil company by output. Gazprom bought stakes in Yukos natural gas assets from Eni SpA and Enel SpA, which won them at auction in 2007.

Rosneft Assets