Yesterday's detention of Khalil al-Marzooq could sharply escalate tensions in the strategic Sunni-ruled kingdom, home to the US Navy's 5th Fleet.
A government statement today quotes Nayef Yousif, head of Bahrain's public prosecution, as saying al-Marzooq is accused of instigating violence and links to a protest faction that authorities blame for bombings and other attacks.
Al-Marzooq, a former deputy parliament speaker, is a top member of Al Wefaq, the main Shiite political bloc. Bahrain's majority Shiites began an uprising in early 2011 seeking a greater political voice. More than 65 people have died in the Arab Spring-inspired unrest.