An oil refinery in the Tyumen region of western Siberia fully halted crude oil processing and petroleum product output following a drone attack this weekend that damaged secondary processing units, two industry sources told Reuters.

On Saturday, Tyumen region Governor Alexander Moor confirmed that a Ukrainian drone struck the Tyumen refinery, triggering a fire at the facility.

According to the sources, the July 25 drone strike set fire to a diesel hydrotreating unit with a capacity of 2.6 million metric tons per year, as well as a combined high-octane gasoline production unit.

The sources said it is difficult to estimate how long repairs will take.

RI-Invest, which owns the Tyumen refinery, did not respond to a Reuters request for comment.