DUBAI, United Arab Emirates (AP) — Two witnesses say four American journalists have been arrested in Bahrain while covering unrest on the anniversary of the tiny island nation's 2011 uprising.

Bahraini officials declined to immediately comment. The U.S. Embassy in Manama says it's "aware of the arrest of four U.S. citizens in Bahrain" on Sunday 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 Sunday night.

It wasn't immediately clear if the journalists worked for a specific media outlet.

The 2011 uprising saw Bahrain's Shiite majority demand greater political rights from the Sunni-led monarchy.