Protesters in Grozny, Chechnya's capital, carried signs and banners demanding an end to the killing of innocents in Myanmar's Rakhine state, where late last month Myanmar security forces launched an unprecedented crackdown on Rohingya Muslims.
"Stop Genocide in Myanmar", "Stop Genocide of Rohingya Muslims", and "Stop Killing Myanmar Muslims," said some of the signs.
Russia's Interior Ministry said around 1.1 million people, including thousands from neighboring regions, gathered in the protests, which ended with noon prayers at Grozny's central mosque, also known as the Heart of Chechnya.
Since the start of the military crackdown on the Rohingya community in Rakhine state on Aug. 25, thousands of Rohingya Muslims have fled to neighboring Bangladesh.
A total of 87,000 mostly Rohingya refugees have arrived in Bangladesh in the past 10 days, the United Nations said on Monday.
Media reports said Myanmar security forces have used disproportionate force, displacing thousands of Rohingya villagers and destroying their homes with mortars and machine guns.
The region has seen tensions simmer between its Buddhist and Muslim populations since communal violence broke out in 2012.
A crackdown launched last October in Maungdaw, where Rohingya make up the majority, led to a UN report on human rights violations and crimes against humanity by security forces.
The UN documented mass gang-rape, killings -- including infants and young children -- brutal beatings, and disappearances. Rohingya representatives have said approximately 400 people were slain during the crackdown.