The son of Mehdi Karroubi (above) said the Iran Dokht paper was targeted due to his father's political activities
The authorities in Iran have closed down the country's biggest-circulation reformist newspaper, Etemaad, accusing it of breaching media laws.
They also suspended publication of a weekly reformist paper whose managing director is the son of one of Iran's opposition leaders, Mehdi Karroubi.
Hossein Karroubi told the BBC that the paper, Iran Dokht, was targeted due to his father's political activities.
Last week Mehdi Karroubi was beaten up by Iranian security forces at a rally.
Both he and the other main opposition leader Mir Hossein Mousavi were taking part in a rally on 11 February, marking the anniversary of the Islamic revolution, when they were reportedly attacked by the government's Basij militia.
Attack on offices
In an interview with BBC Persian television, Hossein Karroubi said that a few days ago, an Iranian government official had spoken to his mother, the proprietor of Iran Dokht.
The official had criticised the political stance of the opposition leader.
Hossein Karroubi said that three months ago there had been an attack on the offices of the journal and the attackers had taken "five or six" computer drives with them.
Publication of the newspaper Etemaad was suspended by Iran's Media Supervision Board, which says it was responsible for repeated press offences.
Observers say that on Monday it published a story on the reaction to the emergence of a film showing the police attack on Tehran university last June, just three days after the election.
Press watchdog official Mohammad Ali Ramin told state-run television later that the ban "was a bitter decision for us but it was done due to repeated breaking of the law," news agency AFP reported.
"The decision was taken with a degree of leniency... Its licence was not revoked and its case was referred to the judiciary," Mr Ramin, who is also the deputy culture minister for media affairs, was quoted as saying.
A third publication, Sina, a weekly provincial newspaper, was also banned, accused of not operating in line with the constitution.