Bahraini officials declined to immediately comment. The US Embassy in Manama says it's "aware of the arrest of four US citizens in Bahrain" yesterday but that it cannot discuss the case due to privacy concerns.
The witnesses spoke on condition of anonymity for fear of arrest. They say one of the four was arrested in the largely Shiite community of Sitra, south of the capital. They say the other three were arrested later last night.
It wasn't immediately clear if the journalists worked for a specific media outlet.