Human Rights Watch says the authorities in Eritrea are punishing the relatives of people accused of evading forced military conscription.
The campaign group says it has spoken to parents who were evicted from their homes, and an 80-year old man who was detained for failing to hand over his youngest son.
There are other cases where people were forced to sleep on the streets.
Eritrea has a policy of indefinite national service – which is often cited as a reason why thousands of young Eritreans try to flee to Europe.
Round-ups by the military intensified as a result of Eritrea’s recent involvement in the civil war.