Conor McGregor has sent his sympathies to MMA and boxing star Francis Ngannou after the death of his 15-month-old son.

Tributes poured into the former UFC heavyweight champion as the news emerged from Cameroon that the 37-year-old's infant had tragically passed away. Earlier on Monday, Ngannou made an emotional post to social media that suggested the devastating news was true.

"What's the purpose of life if what we're fighting tooth and nail to get away from is what finally hit us the hardest!?" the Cameroonian-French fighter said. "Why is life so unfair and merciless? Why does life always take what we don't have? I'm f*****g tired"

McGregor was among the first to respond to the mixed martial artist now under the PFL banner. The Irishman sent his condolences to Ngannou following his loss. The Irish father-of-four said: "I am so sorry to hear of your loss Francis, my prayers are with you and your family at this time."

Ngannou's MMA coach at gym Xtreme Couture, Eric Nicksick also sent an emotional message too. The head coach said: "It’s been a heavy few days, words can’t express the pain we all feel for the Ngannou family during this time.

"Please keep Francis and his family in your heart, and may this be a reminder of the fragility of life. Say “I love you,” more often, tomorrow isn’t guaranteed."

Boxing promoter Frank Warren added his sympathies as a whole host of the MMA world expressed their sadness. "Thoughts and prayers are with @francis_ngannou and his family. Terribly sad news," said Warren.

Conor McGregor has offered his sympathies to Francis Ngannou (
Image:
Getty Images)

Ex-UFC champion Cris Cyborg posted: "Dear lord, I pray you comfort Francis and his family. Surround him with your love and ensure he is protected by your guidance as he grieves this loss.

"Give him the strength to know that heaven is eternal and they will be together soon as this life is just a blink of an eye. I ask this in your name. Amen."

Ngannou has since posted on Instagram a touching farewell message to his son. It reads: "Too soon to leave but yet he's gone. My little by, my mate, my partner Kobe was full of life and joy. Now he's laying without life. I shouted his name over and over but he's not responding.

"I was my best self next to him and now I have no clue of who I am. Life is so unfair to his us where it hurts the most.

"How do you deal with such a thing? How can you live with it? Please help me if you have an idea because I really don't know what to do and how to deal with this."