Five men and one woman were detained on May 14 and taken to Tehran's Evin prison, the Baha'i International Community said on its news website (www.bahai.org).
A relative of 57-year-old Behrouz Tavakkoli, one of those detained, told Reuters in an e-mail that intelligence agents who came to Tavakkoli's house took Baha'i books, papers and documents, and also other items such as computers and CDs.
Subsequently, the relative said Tavakkoli's wife obtained a reference number for her husband's case from Iran's Revolutionary Court, which handles cases that include issues considered a threat to national security.
It was not immediately clear what charges were levelled against the six Baha'is, whose members say they face discrimination and persecution in the Islamic Republic.
In Tehran, Iran's Foreign Ministry spokesman said any such cases were a judicial matter when asked for details at a news conference. There was no immediate comment from the judiciary.
Baha'is say hundreds of their faith have been jailed and executed since Iran's Islamic revolution in 1979. The government denies it has detained or executed people for their faith.
The Baha'i faith originated in Iran 150 years ago and Baha'is say the faith has 5 million adherents worldwide, including an estimated 300,000 or more in Iran.
The Baha'i International Community said the six people detained were members of a committee that tends to the needs of Baha'is in Iran. It said a seventh member, a woman, was detained in March in the eastern city of Mashhad.
