In the Norwegian capital, Oslo, a spokesman for the Norwegian joint command said the Norwegians were slightly injured.
"Two Norwegian officers were injured - it was minor not life threatening - and two other Norwegians suffered superficial injuries," Lieutenant-Colonel John Inge Ogland said.
It was the first time a Finnish soldier was killed on duty in Afghanistan, where the neutral Nordic country has some 70 peacekeepers.
Norway, a Nato-member, has 650 troops in the country, including some 100 at the Maymana base.
Meanwhile, in Kabul on Wednesday, a new suicide blast struck, killing a policeman and wounding six Afghans and a foreigner, according to police and a witness.
"Let the people of Iraq vote if they want the US to stay or leave"