Former MMA fighter Geronimo dos Santos has died at the age of 45 after drowning in a river in Brazil, according to reports. 

Dos Santos, commonly known by his fight nickname 'Mondragon', reportedly disappeared after diving into the Rio Negro near Sao Gabriel da Cachoeira last Friday.

Local reports claim that divers from the Fire Department quickly began searching for Santos before recovering his body on Monday morning. 

The reports claim that Santos' body was found submerged beneath rocks along the riverbed. 

His death was confirmed by the municipality of Sao Gabriel da Cachoeira. A statement read: 'In this moment of grief, we express our deepest condolences to all family and friends. 

'May God grant them strength and comfort to overcome this great loss.'

Dos Santos fought for a number of different mixed martial arts promotions across South America, Europe and Asia, including RIZIN and Mr. Cage. 

He signed with the UFC back in 2012 and was scheduled to fight against Gabriel Gonzaga at UFC 153 in Rio de Janeiro but was forced to withdraw.

Santos tested positive for Hepatitis B, preventing him from being medically cleared. 

He was later released by the UFC after being unable to compete under North American commission regulations.

Overall, Dos Santos had 72 professional MMA fights, winning 45 of those. 

His last fight came back in April, where he secured a first-round knockout victory over ex-UFC heavyweight Aleksei Oleinik in the Bare Knuckle Fighting Championship.

He had then been scheduled to fight against another former UFC star, Andrei Arlovski, in June but eventually withdrew from the bout.