Afghan police say a roadside blast has killed three Germans near Kabul.
Police say one other person was wounded in Wednesday's explosion, which targeted a two-vehicle diplomatic convoy.
NATO's International Security Assistance Force says it is aware of the attack but did not provide further details.
Roadside bombings are frequent in Afghanistan. About 50,000 NATO and U.S.-led coalition troops are battling a resurgent Taleban movement and helping with reconstruction projects in Afghanistan.
Some information for this report was provided by AP and Reuters.