Inside the Saudi prison that's home to new wave of jihadis

Saudi prisoners play volleyball at Ha'er Prison in Saudi Arabia July 6, 2015. REUTERS/Faisal Al Nasser

RIYADH (Reuters) - The man visible on the block's control room monitor, pacing his small cell in uniform grey robe, is one of a rising number of security prisoners in Saudi Arabia, where the wars in Syria and Iraq have led to a surge in domestic jihadist activity.

Until last year, the population of inmates at security prisons like Ha'er, just south of Riyadh, had been dropping as those detained during an al Qaeda uprising a decade ago were gradually released.