The explosion in the Afghan capital, Kabul, on Thursday left at least 40 dead and caused serious casualties, officials and witnesses said.
Photographs sent by witnesses showed what appeared to be serious damage at the site and a number of dead and wounded on the ground.
The blast happened at a compound comprised of the Afghan Voice news agency, a Shia cultural centre and religious school.
The Tebyan centre is located in the Shiite-dominated Dasht-e-Barchi neighbourhood in the west of the capital.
People had gathered for discussions to mark the 38th anniversary of the Soviet invasion of Sunni-majority Afghanistan, with most of those attending students.
The attack was carried out by one bomber wearing a suicide vest and was followed three other blasts in the same area.
It's the latest in a series of attacks to hit Afghan media groups in recent years, and follows an attack on a private television station in Kabul last month.
According to a report this month by media freedom group Reporters without Borders, Afghanistan is among the world's most dangerous countries for media workers with two journalists and five media assistants killed doing their jobs in 2017.