The head of a checkpoint in the town of Altanbulag told AFP that more than 3,000 Russians had entered Mongolia via the crossing since Wednesday, most of them men.
Russia is currently facing significant battle reversals in Ukraine seven months into the war, prompting President Putin to take steps to increase military strength.
Russia Ukraine war: Kyiv s action to reclaim Russia-occupied areas in the Kharkiv region forced Moscow to withdraw its troops to prevent them from being surrounded, leaving behind significant numbers of weapons and munitions in a hasty retreat as the war marked its 200th day on Sunday.
Russia has called a U.S. intelligence report on the purchasing plan “fake.” But U.S. officials say it shows Russia’s desperation with the war in Ukraine and that Moscow could buy additional military hardware from North Korea.