Jose Aldo will not fight Conor McGregor in Las Vegas on July 11.

The featherweight champion was due to defend his title against the Dubliner at UFC 189 but has withdrawn due to a rib injury.

McGregor will now face Chad Mendes - who was twice challenged for the title - for the interim featherweight title.

McGregor spoke about Aldo's decision on ESPN last night, saying the Brazilian was "scared for his life."

"We cannot force him to step inside and face me.

"I feel he is afraid. The doctors have cleared him to fight ... but he has still pulled out," McGregor said.

They can run. But they can't hide.

— Conor McGregor (@TheNotoriousMMA) July 1, 2015

Aldo's participation in the bout has been in doubt since a training injury in Brazil last week. There were conflicting reports about Aldo's condition, but UFC president Dana White announce on ESPN last night that the defending champion will not be fit to fight.

"Aldo's rib is too painful and he will not be fighting," White said on ESPN's SportsCenter.

"Chad Mendes will fight Conor McGregor for the interim belt. It's (Aldo's) decision. I don't feel great about it. We've spent a lot of money promoting this fight and a lot of people were excited. It's definitely disappointing."