|Kashan Afzal (l) and Zain Afzal with their mother|
They reappeared as mysteriously on Thursday in the southern port city of Karachi as they had disappeared from there.
Kashan Afzal and Zain Afzal went missing in August when relatives said about two dozen armed men took them from their home.
One of the brothers told the Associated Press they were released recently. But he said he does not know where they were kept or by whom.
Earlier news reports from Pakistan had said they were nabbed by intelligence agents on suspicion of links to Islamic militants.
Pakistani authorities have repeatedly denied any involvement. Human rights groups had been pressuring Pakistan for their release.
Some information for this report provided by AP and Reuters.