The Interior Ministry said Tuesday there were no injuries or serious damage from the Molotov cocktails. The late Monday attack was a rare attempt to strike government offices in the Gulf state's more than 2-year-old uprising, led by majority Shiites seeking a greater political voice in the Sunni-ruled kingdom.
In the past, police stations, security vehicles and personnel have been targeted, but government or royal compounds have been largely untouched.
The ministry offered few details of the arrests. Online activists, however, said police stormed areas of the capital, Manama, at dawn.
More than 60 people have been killed in Bahrain's unrest. Rights groups place the toll higher.