The four, who were seized in the village of Sal Kalay near the border with Pakistan, are suspected of planning attacks against Afghan and coalition forces. Their names and nationalities were not disclosed.
Meanwhile, the Afghan Interior Ministry says 18 Taliban fighters and four police have been in combat since July 28. It says 14 Taliban were killed in the Garmser district of Helmand Province in the south of the country.
It also says that four Taliban fighters were killed in a battle in Kapisa Province, to the northeast of Kabul.