Russia's unmanned Luna-25 spacecraft has crashed into the Moon after spinning out of control, officials say.
It was Russia's first Moon mission in almost 50 years.
The craft was due to be the first ever to land on the Moon's south pole, but failed after encountering problems as it moved into its pre-landing orbit.
It was set to explore a part of the Moon which scientists think could hold frozen water and precious elements.
Roscosmos, Russia's state space corporation, said on Sunday morning that it had lost contact with the Luna-25 shortly after 14:57pm (11:57 GMT) on Saturday.
Preliminary findings showed that the 800kg lander had "ceased to exist as a result of a collision with the surface of the Moon", it said in a statement.
It said a special commission would look into why the mission failed.
The loss of Luna-25 is a blow to Roscosmos.
Russia's civilian space programme has been in decline for several years, as state funding is increasingly directed towards the military.
Russia was racing to the Moon's south pole against India, whose Chandrayaan-3 spacecraft is scheduled to land there in the coming days and send a rover to explore the rocks and craters, gathering data and images to send back to Earth.
Parts of the Moon's south pole remain permanently in shadow, which makes finding water a possibility.
A spokesperson for the Indian space agency Isro described the Luna-25 crash as "unfortunate".
"Every space mission is very risky and highly technical. It's unfortunate that Luna-25 has crashed," they told the BBC.
Roscosmos had acknowledged that the Luna-25 mission was risky and could fail.
The craft launched from Vostochny Cosmodrome in the far eastern Amur region of Russia on 11 August, and then successfully entered the moon's orbit on Wednesday of this week.
It was expected to make history by making a soft landing on Monday or Tuesday, just days before the Indian touchdown.
No country has ever landed on the Moon's south pole before, although both the US and China have landed softly on the Moon's surface.
Luna-25 was Russia's first Moon mission since 1976, when it was part of the Soviet Union.
That mission, Luna-24, landed successfully.