The teenage daughter of renowned Russian mixed-martial-arts (MMA) fighter Fyodor Yemelyanenko has been hospitalized after reportedly being assaulted by an unidentified man, an incident that comes amid the fighter's standoff with Chechen strongman Ramzan Kadyrov over MMA fights between children.

Russian media reported on October 12 that the assailant punched Yemelyanenko's 16-year-old daughter in the chest late last week while she was walking on the street.

"We have admitted a 16-year-old girl who, according to the doctor treating her, was beaten up by a man," the state-owned R-Sport news agency quoted a source at a Moscow city children's emergency room as saying.

The news agency did not name the girl but reported that the source confirmed that she was Yemelyanenko's daughter.

The Russian newspaper Moskovsky Komsomolets reported earlier in the day that the daughter of a "world heavyweight champion" was assaulted late last week and hospitalized this week after suffering pain throughout the weekend.

The newspaper did not identify Yemelyanenko by name in the report but made it clear the incident involved his daughter, describing her father as "a world champion who criticized exhibition fights between children that were held last week in Chechnya."

The Russian sports daily Sovetsky Sport later in the day reported that the emergency room confirmed that it had admitted a patient named Maria Yemelyanenko.

Kadyrov's Fights 'Unacceptable'

Yemelyanenko, the chairman of Russia's MMA Union, grabbed national headlines last week when he called the October 4 fights, in which three of Kadyrov's sons participated and which were broadcast on national television, "unacceptable" due to the risk of permanent injury and psychological harm that the children faced.

He said that the contests were billed as "exhibitions" but that "in fact, viewers witnessed real fights."

WATCH: Outrage Over Child MMA Match In Chechnya

A close associate of the Kremlin-backed Kadyrov, who rules war-scarred Chechnya like his personal fiefdom and has been accused of targeting political opponents with violence both in Russia and abroad, responded to Yemelyanenko's criticism with what appeared to be a veiled threat.

"Whoever the man is, he will have to be accountable for every word he uttered regarding my dear nephews," Adam Delimkhanov, Kadyrov's cousin and a federal lawmaker, wrote on Instagram on October 6. He called Yemelyanenko a "coward."

Kadyrov wrote on Instagram that Yemelyanenko was "wrong" and acted dishonorably in criticizing the fights, though he later called on supporters to refrain from heaping abuse on the fighter.

A Moscow city police spokesman said police were looking into the reported incident. Journalist Eva Merkacheva, who broke the story for Moskovsky Komsomolets, wrote on Facebook that a criminal case had been opened into alleged "assault."

Kadyrov Untouchable?

The standoff between Kadyrov and Yemelyanenko has cast a fresh spotlight on tensions between the Chechen leader and the federal center.

Russian President Vladimir Putin has largely allowed Kadyrov to run Chechnya as he sees fit in exchange for his merciless crackdown on Islamist separatists in the mainly Muslim region. Rights activists say he ignores Russian law, and senior officials in Moscow have bristled at what they see as Kadyrov thumbing his nose at the Kremlin.

Putin, himself a judo enthusiast, has publicly voiced his admiration for Yemelyanenko. "Thanks to him, and him alone, [MMA] has become so popular in our country," Putin said of Yemelyanenko in the ring following one of his fights.

The Kremlin's ombudswoman for children's rights has said her office is investigating the MMA fights between children.

Putin's spokesman, Dmitry Peskov, said about the fights last week, "If all of this is true, then probably a live broadcast of a child's knockout is the reason for the proper supervisory authorities to closely look into this matter."

With reporting by Moskovsky Komsomolets, R-Sport, Sovetsky Sport, RIA Novosti, AP, and Meduza.io