Russia's space agency on Saturday said there had been an "abnormal situation" involving the Luna-25 spacecraft as it prepared for its moon landing.
"During the operation, an abnormal situation occurred on board the automatic station, which did not allow the manoeuvre to be performed with the specified parameters," Roscosmos said in a short statement.
Luna-25 lander in moon's orbit
The agency went on to say that specialists were analyzing the situation without providing more detail.
The lander successfully entered the moon's orbit on Wednesday following its launch on August 10 in Russia's first such mission in nearly half a century.
It is unclear whether the incident will delay the moon landing which is scheduled to take place on Monday.
The craft is expected to remain on the lunar surface for a year, where it will collect samples and analyse samples. Russia is looking to establish a space station on the moon by 2040.
Russia's space ambitions
Russia is looking to build on the Soviet Union's space program amid uncertainty over future collaboration with the West, due to Russia's war in Ukraine.
The Soviet Union was the first country to land on the moon in 1959. But the space race eventually shifted to Mars and other missions.
Since the 1991 fall of the Soviet Union, Russia has failed to send probes beyond the Earth's orbit.
Roscosmos indicated in July 2022 that it planned to pull out of the International Space Station in 2024 in order to launch its own space station.
