According to TASS, cosmonaut Anatoly Ivanishin reported this to the Mission Control Center.
“We found a possible leak,” Ivanishin said.
It is noted that the Mission Control Center recommended that the cosmonauts seal the alleged leak with adhesive tape.
Also, the astronauts were asked to send photos and videos of the alleged leak.
Earlier in the Russian segment of the ISS, the "Electron-VM" oxygen production system failed.