A drone strike at a Russian refinery near the border with Ukraine caused a massive explosion and fire, causing workers to shut down operations at the facility. Video of the kamikaze drone made the rounds on the internet and accompanied accusations of a Ukrainian attack.

The attack took place at the Novoshakhtinsk oil processing plant in southwestern Russia, the Associated Press reported.

Workers near where the drone pounded the facility captured footage of the strike. The video was shared on Russian social media, and viewers could hear the workers commenting as they filmed the drone as it passed overhead and then rammed into the refinery.

“Do you think it’s Ukrainian?” one of the workers asked, according to a translation provided by the Guardian.

“Of course not,” another replied.

The drone then momentarily disappeared from sight, leading one of the workers to ask, “Where’d it go?”

Suddenly, a massive explosion could be seen at the refinery.

“F***!” the workers yelled as a ball of fire and plume of smoke grew.

Russian state television ran the footage as well as video of firefighters tackling the blaze, the AP said, adding that no one was hurt.

The outlets followed the imagery with accusations of a Ukrainian attack. The refinery told the press that the strike was actually carried out by two drones, which it described as a “terrorist” act. The state-run Tass news agency claimed that two Ukrainian drones had flown over the plant and that one of them rammed into a heat exchanger, according to Bloomberg. Vasily Golubev, the governor of the Rostov-on-Don region where the strike occurred, said fragments of two drones were found on the plant’s property.

Ukrainian officials have yet to claim responsibility for the drone strike.

Drones have been one of the top military items the U.S. has been sending to Ukraine in its efforts to stop Russia’s attempt to take over the former Soviet-bloc nation.