Diane Ala'i, the Baha'i International Community's UN representative in Geneva, confirmed the arrests took place on February 10, the eve of the 31st anniversary of Iran's Islamic Revolution.
The arrests are the latest in a string of such detentions that have escalated since the disputed Iranian presidential election last summer, and which often coincide with antigovernment protests.
On January 3, security forces arrested 10 Baha'is after protests during the Ashura holidays.
The Tehran prosecutor has accused the Baha'is of "organizing the Ashura chaos" and also "sending the images of this chaos abroad."
The regime has officially forbid Baha'i activism in Iran since 1983. Baha'is say hundreds of their followers have been jailed and executed since the Islamic Revolution.
The government denies it has detained or executed people for their religious beliefs. The Baha'i faith was founded in Iran some 150 years ago and it claims to have 5 million followers worldwide, including an estimated 300,000 or more in Iran.