Sharq Editor-in-Chief Ahmad Gholami and his political and international editors were taken from the newsroom by security forces, the Saham news website said. It did not say if any reason was given for their arrest.
The newspaper resumed publishing in April after a three-year ban that reformists regarded as an attempt by hardline rulers to silence critics of President Mahmoud Ahmadinejad.
Its Wednesday edition, which like many Iranian newspapers led with the arrest in London of WikiLeaks founder Julian Assange, did not mention the detention of its own senior staff.
Sharq was closed in 2007 for publishing an interview with a “counter-revolutionary” poet abroad.
At least four pro-reform publications were banned and many journalists detained following street protests that broke out after Ahmadinejad’s re-election in June 2009. Dozens of moderate journalists are still in jail.
On Sunday, opposition websites reported that prominent journalist and human rights activist Emadeddin Baqi was requested to report to jail to serve a sentence which had been confirmed by an appeals court.
(Editing by Mark Heinrich)