BERLIN — Shareholders of German energy company Uniper on Monday approved a rescue package for the gas supplier, clearing the way for its nationalization.

The government announced its plan to nationalize Uniper in September, expanding state intervention in the power sector to prevent an energy shortage resulting from Russia’s war in Ukraine. The deal built on an initial rescue package agreed to in July and features a capital increase of 8 billion euros ($8.5 billion) that Germany will finance.

As part of the agreement, the government will gain a nearly 99% stake in the energy supplier, which before now was controlled by Finland-based Fortum. The Finnish government has the largest stake in Fortum.

Uniper said its shareholders “approved the proposed capital measures by a large majority” at an extraordinary general meeting on Monday.

Germany’s economy minister said he expects the European Commission to approve the bailout before Christmas.

“This is a significant step,” Robert Habeck told reporters in Brussels, adding that Uniper supplies about a third of all gas customers in Germany. “You can see that the rescue of Uniper and all the debates surrounding this weren’t just a game, but that it really is crucial for the security of Germany’s energy supply that this company continues to exist.”

Before the war in Ukraine the company bought about half of its gas from Russia, which started cutting deliveries to Germany in June and hasn’t supplied any gas to the country since the end of August.

The company has incurred huge costs as a result of those cuts because it was forced to buy gas at far higher market prices to meet its supply contract obligations. Last month, Uniper said it had initiated proceedings to seek damages from Russia’s Gazprom at an international arbitration tribunal in Stockholm.

Habeck said the German state doesn’t intend to remain the owner of Uniper permanently.

Environmental groups have called on the government to use its stake in the company to steer it away from new fossil fuel projects, such as natural gas projects off the coast of Australia.