As a result of African impatience with the pace of reforms and then in opposition to increased repression new black political parties had formed. They agitated both politically and violently sometimes resorting to sporadic acts of sabotage. At the forefront of this move was the Zimbabwe African Peoples Union (ZAPU), mostly Ndebele, led by Joshua Nkomo. It was shortly joined by the Zimbabwe African National Union (ZANU), mostly Shona, a breakaway group under Ndabaningi Sithole. After the collapse of the federation in 1963, both ZAPU and ZANU were banned and the majority of their leaders imprisoned.