(CNN) New York Mayor Bill de Blasio on Friday vowed to close the Rikers Island jail complex.

"It will take many years," the mayor said at a news conference. "It will take many tough decisions along the way. But it will happen."

De Blasio set a timeline of 10 years to reduce the overall jail population in the city, which he said would allow for a "complete departure of all inmates from Rikers Island."