Underworld figure Tony Mokbel has been flown to a Melbourne hospital in a serious condition after being stabbed at Victoria's maximum-security Barwon Prison.
Another prisoner, 31, was also attacked and has been taken to hospital in a serious condition, a Corrections Victoria spokesperson said.
Mokbel, sentenced to 30 years in prison in 2012, was the mastermind behind an elaborate drug syndicate known as The Company.
He was arrested in Greece in June 2007, 15 months after fleeing Melbourne while on bail during a trial on cocaine importation charges.
A Victoria Police statement said emergency services were called to the prison, in Lara southwest of Melbourne, following reports of a stabbing about 3:45pm today.
Aerial vision indicates that Mokbel, 53, was stabbed in an outside recreational area of the prison.
Paramedics worked on him on a pathway before he was transferred into an air ambulance and flown to the Royal Melbourne Hospital.
The ABC understands Mokbel suffered three stab wounds.
More to come.