Russian oil company Bashneft, part of state-controlled giant Rosneft, has installed metal mesh at its refineries to protect them from drone attacks from Ukraine, Russian media reported on Friday, quoting Radiy Khabirov, the head of the Bashkortostan region where Bashneft is based.

“We don’t stop there. There are a number of solutions there, which I won’t talk about yet. They are classified. But believe me, we worry about this very much,” the Bashinform agency quoted Khabirov as saying.

This year, Ukraine has intensified attacks on oil refineries in Russia, which have reduced Russian refining capacity, and which, reportedly, have the White House concerned about rising international prices.

The United States has repeatedly urged Ukraine to halt its drone attacks on Russian oil refineries due to Washington’s assessment that the strikes could lead to Russian retaliation and push up global oil prices, the Financial Times reported last month, citing sources familiar with the exchange.