Three Germans killed in Afghanistan
They were travelling on a road about 10km southeast of Kabul.
Nato’s International Security Assistance Force (ISAF) said it was aware of an explosion near a military base but did not know how many casualties there were.
Isaf also said the blast was caused by a land mine.
Amir Mohammad, a police officer, said it was not clear if the mine was recently planted or if it was an old one.