Residents said tight security was in place for the special session of weekly prayers in a mosque at Diraz, a Shia village west of Manama.
The interior ministry ordered a strong police presence following deadly bombings at Shia mosques in Saudi Arabia and Kuwait carried out by Sunni extremists over the past two months.
The joint prayers were a show of Bahraini “unity in the face of those plotting against the Arab and Islamic world”, said Justice and Islamic Affairs Minister Sheikh Khaled bin Ali Al-Khalifa.
Bahraini authorities, backed by volunteers, have stepped up checks on those entering mosques for Friday prayers in the wake of the attacks elsewhere in the Gulf.
Bahrain is the only Arab monarchy of the Gulf with a Shia majority, which has been demanding political reforms- AFP