At first, crew members held off on troubleshooting the issue, since the leak wasn't major.
The crew has since patched the leak using Kapton tape, Roscosmos reported on Monday.
That wasn't considered any major risk, but in August 2020, that already elevated rate increased fivefold, from 0.6 to 3.1 pounds of air per day, according to Russian news agency Ria Novosti.
At first, crew members hunkered down in the Zvezda module while they tested the ship's other sections; when they couldn't find evidence of leaks in those sections, they determined the leak was likely in Zvezda itself.
"We believe that we have really identified the probable leakage area," Ivanishin said, according to Russian news agency TASS.
The station's Russian segment houses some of the station's oldest modules.
Crew members fixed the system by Saturday, according to Roscosmos
This latest leak also wasn't the first on the Russian side
In August 2018, crew members discovered a 2-millimeter drill hole in part of a Russian Soyuz spaceship that was docked to the station