"The strike was conducted in a remote locality in Piri area of Musa Khil district late on Friday evening," district chief Gulab Mangal said.
Mangal said the airstrike was conducted by the US-led coalition war planes in the province, 150 km southeast of Kabul.
A Taliban hideout, together with weapons and ammunition, was also destroyed by the attack, he added.
Earlier on Saturday, the Afghan Defense Ministry also confirmed in a statement the elimination of 50 militants in Khost, but did not give the details.
The Afghan security forces have beefed up security operations against militants as the Taliban militants and ISIS fighters have been attempting to take territory and consolidate their positions across the country.
The militant group has yet to make comments.