JOHANNESBURG — South Africa’s police are investigating each of the 34 killings of striking mine workers and are also looking into allegations that more than 150 arrested miners have been beaten in police custody, the spokesman for the police directorate of complaints said Monday.

The spokesman said more than 150 arrested miners have asserted that they were beaten to get them to implicate their colleagues in the killings of two police officers.

The news came as President Jacob Zuma was questioned by the African National Congress national executive committee over police shootings that wounded another 78 strikers at the Lonmin PLC platinum mine on Aug. 16.

In the fallout from the killings, the mine strike has strengthened. Only 13 percent of workers reported for duty Monday — down from 30 percent Friday and 50 percent Saturday.