The former Abuja Football College stars were signed for a combined €5-million (R82-million) and penned four-year contracts with the Italian club.
Umar (19) is a striker and Nura (18) is a right-back.
The duo spent the 2015/2016 season on loan at Roma from Serie B side Spezia, but have now made their moves permanent for €2.5-million each.
— AS Roma English (@ASRomaEN) June 21, 2016
Roma have also completed the permanent signing of Italy forward Stephan El Shaarawy from AC Milan for €13-million.
The 23-year-old has signed a four-year permanent contract with the Giallorossi after a successful six-month loan deal.