MILAN, April 3 (Reuters) - Energy storage group VTTI will get a 70% stake in Italy's biggest liquefied natural gas (LNG) terminal, with grid operator Snam owning the rest, the Milan-listed group said on Wednesday, announcing a deal to be finalised by year-end.

Snam, which is controlled by the Italian government, said in a statement it had exercised its pre-emption right to increase its stake in the infrastructure dubbed Adriatic LNG to 30% from 7.3%.

The move comes after ExxonMobil and QatarEnergy last week agreed to sell their stakes in the terminal to a consortium led by Dutch group VTTI. It confirms what two sources had told Reuters.

"This operation strengthens Snam's presence in LNG infrastructure, which is increasingly strategic for the security and diversification of Italy's energy supplies," Snam CEO Stefano Venier said, adding the group would support the terminal's expansion projects.

Snam did not give financial details for the deal while sources had previously said the deal would value the entire terminal around 800 million euros ($866 million) including debt.

REPLACING RUSSIAN GAS

The terminal is located about 9 miles (15 km) off the Veneto coastline and has a regasification capacity of 9 billion cubic metres (bcm) of natural gas per year.

Europe has increased LNG imports after Russia's invasion of Ukraine in 2022 drastically curtailed gas coming through pipelines.

Snam holds stakes in all the remaining LNG terminals currently operating in Italy for a total regasification capacity of about 23 bcm.

The group will set up an additional floating LNG terminal offshore the city of Ravenna at the beginning of next year, increasing Italy's regasification capacity to 29 bcm, equal to the gas Italy used to import from Russia via pipeline.

The closing of the transaction is subject to regulatory authorisations.

Commodity trader Vitol -- which is a shareholder in VTTI together with Australia's IFM and Abu Dhabi's ADNOC -- has also agreed to buy Italian oil refiner Saras.

($1 = 0.9234 euros) (Reporting by Francesca Landini; Editing by Angus MacSwan; editing by David Evans)