Italy on Saturday summoned Russia's ambassador after Moscow announced it was putting a subsidiary of Italian heating firm Ariston under the "temporary management" of state energy giant Gazprom.

"The government requests clarification on the matter of the nationalization of the Ariston Thermo Group," Foreign Minister Antonio Tajani said on X.

He said he asked the top official in Italy's foreign ministry to summon Russia's ambassador, adding that Rome was "working also with Brussels, in conjunction with Germany", after Bosch was also targeted.

Tajani earlier said he had spoken to Ariston's top managers and Rome "stands alongside businesses, ready to protect them in all international markets".

An EU spokesman condemned the move as "yet another proof of Russia's disregard for international law and rules" and called on Moscow to reverse it.

The move was announced in a Russian decree published Friday and signed by President Vladimir Putin.

It transfers control over 100 percent of the shares in Ariston Thermo Rus, owned by Ariston Holding NV, and 100 percent of shares in BSH Household Appliances, owned by BSH Hausgerate GmbH, to Gazprom Household Systems, a subsidiary of Gazprom.

In a statement, Ariston Group said it had been active in Russia for almost 20 years and had "very correct relations with the local institutions".

It said it was "extremely surprised" by the decree, of which it said it had no advance notice.

"While we wait for an explanation on the unexpected action, we are assessing its implications, including from a governance and managerial standpoint," it said.

Since invading Ukraine, Moscow has taken the Russian subsidiaries of a number of Western companies — notably French food giant Danone and Danish brewer Carlsberg — under what it calls "temporary management control".

It cast the moves as a response to Western sanctions on Russian companies.

Western officials and some of the companies have blasted Moscow's "nationalization" of private property.

'Arbitrary and hostile'

Ariston Group has a water heating manufacturing facility located outside St. Petersburg, with around 200 direct and indirect employees, producing products for the local market.

The company said there was also "a local product development centre of excellence and a commercial head office in Moscow, coordinating around 100 employees also active on local commercial branches" throughout Russia, operating under the Ariston brand.

The group had a turnover of about 100 million euros in Russia in the 2023 financial year, it said, and held a "significant asset base".

The EU spokesperson said Saturday: "Russia confirms to be an unpredictable actor also in the economic field, and has created a business climate which is arbitrary and hostile towards foreign investors.

"The European Union calls on Russia to reverse these measures and seek acceptable solutions with European companies targeted by them."

BSH Hausgerate told AFP it was in discussions with Gazprom Household Systems and would not be making any other comments for the time being.