The missile assault on the city of Voronezh announced by the Ukrainian military was the latest blow to Russia's military industry inflicted by long-range strikes.
The Ukrainian General Staff said it had used air-launched cruise missiles to hit the facility, which it described as a "critical component" in Russia's defence production in the city less than 200km from the Ukrainian border.
"It manufactures electronics used in Russian missiles, in particular for the Iskander tactical missile system," it posted on Telegram.
Voronezh Regional Governor Alexander Gusev, writing on Telegram, described the main target of the attack as "an industrial enterprise" on the left bank of the Voronezh River in the provincial capital.
"We have sustained extremely heavy losses today. As a result of a missile attack on the city, five people were killed," Gusev said.
"Several dozen citizens sought medical help but most were sent home after receiving treatment."
Gusev said 10 apartment buildings and six private homes were damaged.
Earlier, the governor said Russian air defences had destroyed several high-speed targets over the city.
Video shot from a car driving past the scene, verified by Reuters, showed vast plumes of black smoke billowing out of at least two places in the factory.
Robert Brovdi, commander of Ukraine's drone forces, said his units had taken part in the operation alongside other forces.
In recent months, Ukraine has hit several Russian military production facilities, especially missile manufacturers.
Despite Ukraine's increasing capabilities, Russian air attacks still have far greater reach into Ukraine.
A top Ukrainian drone maker, General Cherry, said on Monday that one of its factories had been hit, in a rare disclosure.
Ukrainian drones on Monday attacked Russia's Satellite Communications Centre (SCC) 120km north of Moscow, Russian authorities confirmed following a report by Ukraine's military.
"The functionality of TV broadcasting and news traffic were not disrupted," the press service of the operator of Russian communications satellites said.
It said the effects of the attack were being dealt with and that no staff had been injured.
The SCC was established to broadcast the 1980 Moscow Olympics.
It went on to set up a direct line between the Kremlin and the White House.
It is not known whether it is also used for military purposes.
with DPA
