Responsibility for a drone attack in the Tatarstan region of Russia has been claimed by Ukraine.

Tatarstan sits about 807 miles from the Ukraine-Russia border and is the deepest strike into Russian territory since the beginning of hostilities between the two countries. 12 people were injured in the attack.

Local authorities reported that the strikes hit the town of Yelabuga, where Russia's drones are believed to be produced, as well as an oil refinery in Nizhnekamsk, which is located nearby.

Yelabuga is located in what is called a "special economic zone," a legal designation meant to attract foreign investment. Iranian Shahed-136 drones used against Russia are said to be assembled there.

Regional leader Rustam Minnikhanov said the drones caused no serious damage to the infrastructure of either location and production was unincumbered.

But Ukraine's military intelligence said the opposite, saying the strike "caused significant destruction of production facilities".

Video circulated shortly after the attacks purporting to show a small aircraft descending onto a building in Yelabuga before exploding, sending a fireball into the air. More drones were spotted south of Moscow on Tuesday morning, local authorities said.

This is the latest in a recently ramped-up Ukrainian drone campaign aimed at striking deep into Russian territory.

Ukraine has warned repeatedly that its army is facing severe ammunition shortages but has set a target of producing a million drones domestically this year.

Ukraine drones were reportedly able to hit a major gas export terminal near St. Petersburg. It was the deepest strike into Russian territory by Ukraine at the time at 775 miles inside the country.