At least eight of the remaining 12 hostages out of 31 bus passengers abducted earlier this year have been freed, said the Afghan intelligence agency.
The freed abductees constitute five men, two men and a teenager, said National Directorate of Security (NDS) in a statement on Tuesday.
The abductees – who were held for nearly nine months – will join their families soon, it added.
At least 31 bus passengers were kidnapped earlier this year on February 24 by unknown armed masked men when they stopped several buses on Kabul-Kandahar highway.
The kidnappers reportedly took the hostages to Shah Joy district in southern Zabul.
Nineteen of those abducted were released on 11 May as a result of an alleged prisoner swap between government and kidnappers.
However the whereabouts of four other hostages is still unclear.
Unconfirmed reports suggested few months ago that some of the remaining hostages had either been killed or died of poor health conditions.