MOSCOW - A Russian energy ministry official told a parliament meeting on Tuesday there were plans to defend oil and gas facilities with missile systems."We are jointly working, including with colleagues from the Russian National Guard, to cover objects, on installing, accordingly, protection systems such as Pantsir," said Artyom Verkhov, director of energy ministry's department for gas industry development.

Ukraine has stepped up attacks on Russian oil infrastructure since the start of the year, hitting numerous large oil refineries in an attempt to cripple Russia's military and curb its army's advances.

Russian oil refining capacity shut down in the wake of Ukrainian drone attacks in the first quarter amounts to about 4.6 million tons (370,500 barrels per day), or some 7% of the total, Reuters calculations show. REUTERS