The seven Bahai leaders are now all in jail, the group says
The Iranian authorities have acknowledged the arrest of a number of members of the Bahai faith, which is considered to be heretical in Iran.
A Foreign Ministry spokesman said the arrests were a judicial matter and he did not give any further details.
The Bahai International Community says a senior member was arrested in March and six more last week; together they make up the entire leadership in Iran.
It says it has about 300,000 members in Iran, where the faith originated.
Relatives said the six senior members were taken to Evin Prison in Tehran on 14 May, after Intelligence Ministry officers raided their homes in the middle of the night.
The Bahai faith is banned by the Islamic revolutionary leadership of Iran.
Hundreds of Bahai followers have been jailed and executed since Iran's Islamic revolution in 1979, the Bahai International Community says.
However, the government denies it has detained or executed people because of their faith.
Canada voiced concern over the arrests on Friday and called for their release.