Ukraine struck a chemical plant in Russia's Tula region for the second time in two weeks as part of a massive wave of overnight drone attacks, according to Russian and Ukrainian Telegram channels.
Regional governor Dmitry Milyayev said an industrial facility in Novomoskovsk, 200 km (125 miles) south of Moscow, had been damaged.
Multiple news reports named it as the Azot plant, which has been described by Ukrainian President Volodymyr Zelenskiy as critical to Russia's production of explosives.
Azot, which describes itself as Russia's largest producer of ammonia and nitrogen fertilisers, was previously hit on June 14, according to Zelenskiy.
Ukraine has intensified drone strikes deep inside Russia this year as part of a strategy to inflict economic pain and undermine Moscow's ability to sustain the war.
Its targets have included oil refineries, terminals and ports as well as industrial facilities.
In some cases it has launched repeat attacks on the same site within a space of a few days or weeks, disrupting efforts to repair damage and restart operations.
Milyayev, the governor, said electricity lines in the Tula region were also damaged and one woman was injured.
State news agency TASS said the quantity of drones fired by Ukraine was the highest this year. The Russian Defence Ministry said 660 were destroyed over 12 Russian regions and Crimea, which Russia annexed from Ukraine in 2014.
