Ramzan Kadyrov is reported to have encouraged Akhmad, Eli and Adam - aged 10, nine and eight respectively - to take part in the full-contact competition and publicised the fights on his Instagram page.
The contest in the capital city of Grozny had similar rules to professional MMA fights and was broadcast on national television in Chechyna and Russia.
The children taking part did not wear helmets or protective gear and were vulnerable to aggressive punching and kicking from their fellow competitors.
One video uploaded by Mr Kadyrov appears to show a young boy crying and wiping blood off his nose after being punched in the face, as a packed crowd including the Chechen leader cheered on the competitors.
The children were rewarded with elaborate gold belts for their victories and given their own background music as they entered the ring, mirroring the conventions of professional martial arts.
Fyodor Yemelianenko, head of the Russian MMA union, posted a statement online saying the competition was “unacceptable and cannot be justified”.
“[There are] kids who are eight-years-old beating each other in front of cheering adults. Is it really so important to organise a spectacle to the detriment of the health of children?,” he asked, warning the fights could cause "irreparable" physical and phycological damage in young children.
He went on to specifically name Mr Kadyrov - who had earlier boasted about the “confident victory” achieved by his son Adam - and said it was “incomprehensible” that state networks would allow such a sport to be broadcast.
Mr Kadyrov was recently re-elected as leader of the Chechen Republic with 98% of the vote and is a close ally of Russian president Vladimir Putin. He has been accused of hundreds of human rights abuses in the past, including the torture and kidnap of rival politicians.
He is a known sports fan and once challenged one of his ministers to a public boxing match after his policies were criticised, according to AP. His Instagram feed contains many videos of him taking part in martial arts.
Register for free to continue reading
Registration is a free and easy way to support our truly independent journalism
By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists
Already have an account? sign in
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies