On Friday, cosmonaut Anatoly Ivanishin informed the Moscow-based Mission Control Centre that the pressure in the compartment had declined by 52 mm Hg to 681 mm Hg over 11.5 hours, while the leak rate had fallen to 4 mm per hour from 7-9 mm per hour.
The cosmonaut noted that the pressure continued to fall, but at a slower pace. He also suggested trying US patches to seal the crack.
Russian space agency Roscosmos earlier told Sputnik that the air leak posed no threat to the crew.
Earlier, Russian cosmonauts sealed the source of the air leak. On Thursday night, they once again closed the hatch to the "leaking" compartment to control pressure.